diff --git a/ai_knowledge_base_v2/apps/admin-web/src/App.vue b/ai_knowledge_base_v2/apps/admin-web/src/App.vue
index 1b90f9d..6d17764 100644
--- a/ai_knowledge_base_v2/apps/admin-web/src/App.vue
+++ b/ai_knowledge_base_v2/apps/admin-web/src/App.vue
@@ -44,6 +44,9 @@ const RetrievalLogView = defineAsyncComponent(
 const UserManagementView = defineAsyncComponent(
   () => import("./components/UserManagementView.vue"),
 );
+const SsoIntegrationView = defineAsyncComponent(
+  () => import("./components/SsoIntegrationView.vue"),
+);
 
 const admin = ref<AdminProfile | null>(null);
 const activeMenu = ref("dashboard");
@@ -608,6 +611,12 @@ async function clearFeishuCache() {
       >
         系统配置
       </button>
+      <button
+        :class="{ active: activeMenu === 'sso' }"
+        @click="switchMenu('sso')"
+      >
+        应用接入
+      </button>
       <button
         :class="{ active: activeMenu === 'records' }"
         @click="switchMenu('records')"
@@ -1003,6 +1012,8 @@ async function clearFeishuCache() {
           v-if="activeMenu === 'content-generation'"
         />
 
+        <SsoIntegrationView v-if="activeMenu === 'sso'" />
+
         <template v-if="activeMenu === 'configs'">
           <div class="page-head inline">
             <div>
diff --git a/ai_knowledge_base_v2/apps/admin-web/src/components/SsoIntegrationView.vue b/ai_knowledge_base_v2/apps/admin-web/src/components/SsoIntegrationView.vue
new file mode 100644
index 0000000..c80b349
--- /dev/null
+++ b/ai_knowledge_base_v2/apps/admin-web/src/components/SsoIntegrationView.vue
@@ -0,0 +1,394 @@
+<script setup lang="ts">
+import { ElMessage, ElMessageBox } from "element-plus";
+import { computed, onMounted, reactive, ref } from "vue";
+
+import { api } from "../services/api";
+import type { SsoAuditItem, SsoClientItem, SsoIdentityItem } from "../types/api";
+import AdminPagination from "./AdminPagination.vue";
+
+const loading = ref(false);
+const savingUrl = ref(false);
+const clients = ref<SsoClientItem[]>([]);
+const userClientUrl = ref("");
+const activeTab = ref("applications");
+const clientDialogOpen = ref(false);
+const editingClientId = ref<number | null>(null);
+const secretDialogOpen = ref(false);
+const revealedSecret = ref("");
+const revealedAppId = ref("");
+
+const identityItems = ref<SsoIdentityItem[]>([]);
+const identityTotal = ref(0);
+const identityPage = ref(1);
+const identityPageSize = ref(10);
+const identityKeyword = ref("");
+const identityClientId = ref<number | undefined>();
+
+const auditItems = ref<SsoAuditItem[]>([]);
+const auditTotal = ref(0);
+const auditPage = ref(1);
+const auditPageSize = ref(10);
+const auditClientId = ref<number | undefined>();
+const auditStatus = ref("");
+
+const clientForm = reactive({
+  appId: "",
+  name: "",
+  redirectUrisText: "",
+  status: 1,
+});
+
+const dialogTitle = computed(() => editingClientId.value ? "编辑接入应用" : "新增接入应用");
+
+onMounted(loadOverview);
+
+async function loadOverview() {
+  loading.value = true;
+  try {
+    const [config, clientList] = await Promise.all([api.ssoConfig(), api.ssoClients()]);
+    userClientUrl.value = config.userClientUrl;
+    clients.value = clientList;
+  } catch (error) {
+    showError(error, "应用接入配置加载失败");
+  } finally {
+    loading.value = false;
+  }
+}
+
+async function savePublicUrl() {
+  savingUrl.value = true;
+  try {
+    const result = await api.saveSsoConfig(userClientUrl.value.trim());
+    userClientUrl.value = result.userClientUrl;
+    ElMessage.success("用户端公网地址已保存");
+  } catch (error) {
+    showError(error, "用户端公网地址保存失败");
+  } finally {
+    savingUrl.value = false;
+  }
+}
+
+function openCreateDialog() {
+  editingClientId.value = null;
+  Object.assign(clientForm, { appId: "", name: "", redirectUrisText: "", status: 1 });
+  clientDialogOpen.value = true;
+}
+
+function openEditDialog(client: SsoClientItem) {
+  editingClientId.value = client.id;
+  Object.assign(clientForm, {
+    appId: client.appId,
+    name: client.name,
+    redirectUrisText: client.redirectUris.join("\n"),
+    status: client.status,
+  });
+  clientDialogOpen.value = true;
+}
+
+async function saveClient() {
+  const appId = clientForm.appId.trim();
+  const name = clientForm.name.trim();
+  if (!appId || !name) {
+    ElMessage.warning("请填写应用ID和应用名称");
+    return;
+  }
+  const redirectUris = clientForm.redirectUrisText
+    .split(/\r?\n/)
+    .map((item) => item.trim())
+    .filter(Boolean);
+  try {
+    if (editingClientId.value) {
+      await api.updateSsoClient(editingClientId.value, { name, redirectUris, status: clientForm.status });
+      ElMessage.success("接入应用已更新");
+    } else {
+      const result = await api.createSsoClient({ appId, name, redirectUris, status: clientForm.status });
+      revealedSecret.value = result.clientSecret || "";
+      revealedAppId.value = result.appId;
+      secretDialogOpen.value = true;
+    }
+    clientDialogOpen.value = false;
+    await loadOverview();
+  } catch (error) {
+    showError(error, "接入应用保存失败");
+  }
+}
+
+async function toggleClient(client: SsoClientItem) {
+  const targetStatus = client.status;
+  try {
+    await api.updateSsoClient(client.id, {
+      name: client.name,
+      redirectUris: client.redirectUris,
+      status: targetStatus,
+    });
+    ElMessage.success(targetStatus === 1 ? "应用已启用" : "应用已停用");
+  } catch (error) {
+    client.status = targetStatus === 1 ? 0 : 1;
+    showError(error, "应用状态更新失败");
+  }
+}
+
+async function rotateSecret(client: SsoClientItem) {
+  try {
+    await ElMessageBox.confirm(
+      `更新后，${client.name} 使用的旧密钥会立即失效。确定继续吗？`,
+      "更新应用密钥",
+      { type: "warning", confirmButtonText: "确认更新", cancelButtonText: "取消" },
+    );
+    const result = await api.rotateSsoClientSecret(client.id);
+    revealedSecret.value = result.clientSecret;
+    revealedAppId.value = client.appId;
+    secretDialogOpen.value = true;
+  } catch (error) {
+    if (error === "cancel" || error === "close") return;
+    showError(error, "应用密钥更新失败");
+  }
+}
+
+async function copySecret() {
+  await navigator.clipboard.writeText(revealedSecret.value);
+  ElMessage.success("应用密钥已复制");
+}
+
+async function switchTab(tabName: string | number) {
+  activeTab.value = String(tabName);
+  if (activeTab.value === "identities") await loadIdentities();
+  if (activeTab.value === "audits") await loadAudits();
+}
+
+async function loadIdentities() {
+  loading.value = true;
+  try {
+    const page = await api.ssoIdentities({
+      clientId: identityClientId.value,
+      keyword: identityKeyword.value.trim(),
+      page: identityPage.value,
+      pageSize: identityPageSize.value,
+    });
+    identityItems.value = page.items;
+    identityTotal.value = page.total;
+  } catch (error) {
+    showError(error, "账号绑定加载失败");
+  } finally {
+    loading.value = false;
+  }
+}
+
+async function searchIdentities() {
+  identityPage.value = 1;
+  await loadIdentities();
+}
+
+async function changeIdentityPage(page: number, pageSize: number) {
+  identityPage.value = page;
+  identityPageSize.value = pageSize;
+  await loadIdentities();
+}
+
+async function unlinkIdentity(item: SsoIdentityItem) {
+  try {
+    await ElMessageBox.confirm(
+      `解除后，${item.userName} 下次从 ${item.clientName} 进入时需要重新核对手机号。`,
+      "解除账号绑定",
+      { type: "warning", confirmButtonText: "解除绑定", cancelButtonText: "取消" },
+    );
+    await api.unlinkSsoIdentity(item.id);
+    ElMessage.success("账号绑定已解除");
+    await Promise.all([loadIdentities(), loadOverview()]);
+  } catch (error) {
+    if (error === "cancel" || error === "close") return;
+    showError(error, "解除账号绑定失败");
+  }
+}
+
+async function loadAudits() {
+  loading.value = true;
+  try {
+    const page = await api.ssoAudits({
+      clientId: auditClientId.value,
+      auditStatus: auditStatus.value,
+      page: auditPage.value,
+      pageSize: auditPageSize.value,
+    });
+    auditItems.value = page.items;
+    auditTotal.value = page.total;
+  } catch (error) {
+    showError(error, "登录审计加载失败");
+  } finally {
+    loading.value = false;
+  }
+}
+
+async function searchAudits() {
+  auditPage.value = 1;
+  await loadAudits();
+}
+
+async function changeAuditPage(page: number, pageSize: number) {
+  auditPage.value = page;
+  auditPageSize.value = pageSize;
+  await loadAudits();
+}
+
+function formatTime(value?: string | null) {
+  if (!value) return "-";
+  return new Date(value).toLocaleString("zh-CN", { hour12: false });
+}
+
+function maskPhone(phone: string) {
+  return phone.replace(/^(\d{3})\d{4}(\d{4})$/, "$1****$2");
+}
+
+function showError(error: unknown, fallback: string) {
+  ElMessage.error(error instanceof Error ? error.message : fallback);
+}
+</script>
+
+<template>
+  <section v-loading="loading" class="sso-page">
+    <div class="page-head inline">
+      <div>
+        <h2>应用接入</h2>
+        <p>让已在其他可信应用登录的学员免验证码进入千问千答，并独立管理密钥、账号绑定和登录审计。</p>
+      </div>
+      <el-button type="primary" @click="openCreateDialog">新增接入应用</el-button>
+    </div>
+
+    <section class="sso-public-url">
+      <div>
+        <strong>用户端公网地址</strong>
+        <p>服务端会使用这个地址生成免登录入口，例如 https://qa.example.com。</p>
+      </div>
+      <el-input v-model="userClientUrl" placeholder="https://qa.example.com" clearable />
+      <el-button :loading="savingUrl" @click="savePublicUrl">保存地址</el-button>
+    </section>
+
+    <el-tabs :model-value="activeTab" @tab-change="switchTab">
+      <el-tab-pane label="接入应用" name="applications">
+        <el-table :data="clients" stripe empty-text="还没有接入应用">
+          <el-table-column prop="name" label="应用名称" min-width="180" />
+          <el-table-column prop="appId" label="应用ID" min-width="180" />
+          <el-table-column label="回跳地址" min-width="240" show-overflow-tooltip>
+            <template #default="{ row }">{{ row.redirectUris.join("、") || "未配置" }}</template>
+          </el-table-column>
+          <el-table-column prop="identityCount" label="绑定用户" width="100" align="center" />
+          <el-table-column label="最近使用" width="180">
+            <template #default="{ row }">{{ formatTime(row.lastUsedAt) }}</template>
+          </el-table-column>
+          <el-table-column label="状态" width="100" align="center">
+            <template #default="{ row }">
+              <el-switch v-model="row.status" :active-value="1" :inactive-value="0" @change="toggleClient(row)" />
+            </template>
+          </el-table-column>
+          <el-table-column label="操作" width="190" fixed="right" align="center">
+            <template #default="{ row }">
+              <div class="sso-row-actions">
+                <el-button size="small" @click="openEditDialog(row)">编辑</el-button>
+                <el-button size="small" @click="rotateSecret(row)">更新密钥</el-button>
+              </div>
+            </template>
+          </el-table-column>
+        </el-table>
+      </el-tab-pane>
+
+      <el-tab-pane label="账号绑定" name="identities">
+        <div class="sso-filters">
+          <el-select v-model="identityClientId" clearable placeholder="全部应用">
+            <el-option v-for="client in clients" :key="client.id" :label="client.name" :value="client.id" />
+          </el-select>
+          <el-input v-model="identityKeyword" clearable placeholder="搜索姓名、手机号或外部用户ID" @keyup.enter="searchIdentities" />
+          <el-button type="primary" @click="searchIdentities">查询</el-button>
+        </div>
+        <el-table :data="identityItems" stripe empty-text="暂无账号绑定">
+          <el-table-column prop="clientName" label="来源应用" min-width="150" />
+          <el-table-column prop="userName" label="学员" min-width="120" />
+          <el-table-column label="手机号" width="140">
+            <template #default="{ row }">{{ maskPhone(row.phone) }}</template>
+          </el-table-column>
+          <el-table-column prop="externalUserId" label="外部用户ID" min-width="190" />
+          <el-table-column label="最近免登录" width="180">
+            <template #default="{ row }">{{ formatTime(row.lastLoginAt) }}</template>
+          </el-table-column>
+          <el-table-column label="操作" width="120" align="center">
+            <template #default="{ row }"><el-button size="small" type="danger" plain @click="unlinkIdentity(row)">解除绑定</el-button></template>
+          </el-table-column>
+        </el-table>
+        <AdminPagination :page="identityPage" :page-size="identityPageSize" :total="identityTotal" @change="changeIdentityPage" />
+      </el-tab-pane>
+
+      <el-tab-pane label="登录审计" name="audits">
+        <div class="sso-filters">
+          <el-select v-model="auditClientId" clearable placeholder="全部应用">
+            <el-option v-for="client in clients" :key="client.id" :label="client.name" :value="client.id" />
+          </el-select>
+          <el-select v-model="auditStatus" clearable placeholder="全部状态">
+            <el-option label="成功" value="SUCCESS" />
+            <el-option label="失败" value="FAILED" />
+          </el-select>
+          <el-button type="primary" @click="searchAudits">查询</el-button>
+        </div>
+        <el-table :data="auditItems" stripe empty-text="暂无登录审计">
+          <el-table-column prop="clientName" label="来源应用" min-width="150" />
+          <el-table-column prop="externalUserId" label="外部用户ID" min-width="190" />
+          <el-table-column label="环节" width="110">
+            <template #default="{ row }">{{ row.action === "ticket" ? "申请授权码" : "兑换登录态" }}</template>
+          </el-table-column>
+          <el-table-column label="状态" width="100" align="center">
+            <template #default="{ row }"><el-tag :type="row.status === 'SUCCESS' ? 'success' : 'danger'">{{ row.status === "SUCCESS" ? "成功" : "失败" }}</el-tag></template>
+          </el-table-column>
+          <el-table-column prop="errorMessage" label="失败原因" min-width="220" show-overflow-tooltip />
+          <el-table-column prop="ip" label="请求IP" width="140" />
+          <el-table-column label="时间" width="180"><template #default="{ row }">{{ formatTime(row.createdAt) }}</template></el-table-column>
+        </el-table>
+        <AdminPagination :page="auditPage" :page-size="auditPageSize" :total="auditTotal" @change="changeAuditPage" />
+      </el-tab-pane>
+    </el-tabs>
+
+    <el-dialog v-model="clientDialogOpen" :title="dialogTitle" width="620px" destroy-on-close>
+      <el-form label-position="top">
+        <div class="sso-form-grid">
+          <el-form-item label="应用名称"><el-input v-model="clientForm.name" placeholder="例如：学员服务 App" /></el-form-item>
+          <el-form-item label="应用ID"><el-input v-model="clientForm.appId" :disabled="Boolean(editingClientId)" placeholder="例如：student-app" /></el-form-item>
+        </div>
+        <el-form-item label="允许回跳地址">
+          <el-input v-model="clientForm.redirectUrisText" type="textarea" :rows="4" placeholder="每行一个完整 HTTPS 地址；不需要回跳时可以留空" />
+        </el-form-item>
+        <el-form-item label="启用应用"><el-switch v-model="clientForm.status" :active-value="1" :inactive-value="0" /></el-form-item>
+      </el-form>
+      <template #footer>
+        <el-button @click="clientDialogOpen = false">取消</el-button>
+        <el-button type="primary" @click="saveClient">保存</el-button>
+      </template>
+    </el-dialog>
+
+    <el-dialog v-model="secretDialogOpen" title="请立即保存应用密钥" width="620px" :close-on-click-modal="false">
+      <el-alert title="密钥只在本次显示，关闭后无法再次查看。请保存到接入应用的服务端密钥管理中，不要放入前端代码。" type="warning" :closable="false" show-icon />
+      <div class="sso-secret-block">
+        <label>应用ID</label><code>{{ revealedAppId }}</code>
+        <label>应用密钥</label><code>{{ revealedSecret }}</code>
+      </div>
+      <template #footer>
+        <el-button @click="copySecret">复制密钥</el-button>
+        <el-button type="primary" @click="secretDialogOpen = false">我已保存</el-button>
+      </template>
+    </el-dialog>
+  </section>
+</template>
+
+<style scoped>
+.sso-page { display: grid; gap: 20px; }
+.sso-public-url { display: grid; grid-template-columns: minmax(250px, 1fr) minmax(320px, 1.3fr) auto; gap: 18px; align-items: center; padding: 20px 22px; border: 1px solid #dce8e4; border-radius: 16px; background: #fff; }
+.sso-public-url p { margin: 6px 0 0; color: #71817d; font-size: 13px; }
+.sso-row-actions { display: flex; justify-content: center; gap: 8px; white-space: nowrap; }
+.sso-filters { display: flex; gap: 12px; margin-bottom: 16px; }
+.sso-filters .el-select { width: 190px; }
+.sso-filters .el-input { max-width: 360px; }
+.sso-form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
+.sso-secret-block { display: grid; grid-template-columns: 90px minmax(0, 1fr); gap: 12px 16px; align-items: start; margin-top: 20px; }
+.sso-secret-block label { color: #6c7d79; }
+.sso-secret-block code { padding: 10px 12px; overflow-wrap: anywhere; border-radius: 8px; background: #f3f7f5; color: #173d34; }
+@media (max-width: 980px) {
+  .sso-public-url { grid-template-columns: 1fr; }
+  .sso-filters { flex-wrap: wrap; }
+}
+</style>
diff --git a/ai_knowledge_base_v2/apps/admin-web/src/services/api.ts b/ai_knowledge_base_v2/apps/admin-web/src/services/api.ts
index daeca4d..4f55f0c 100644
--- a/ai_knowledge_base_v2/apps/admin-web/src/services/api.ts
+++ b/ai_knowledge_base_v2/apps/admin-web/src/services/api.ts
@@ -38,6 +38,9 @@ import type {
   PromptHistoryItem,
   QuestionInsightRefreshResult,
   QuestionInsightSummary,
+  SsoAuditItem,
+  SsoClientItem,
+  SsoIdentityItem,
   TopicSessionRecord,
   TopicSummaryRecord,
 } from "../types/api";
@@ -263,6 +266,27 @@ export const api = {
   configs: () => request<SystemConfigItem[]>("/admin/config"),
   saveConfig: (payload: Record<string, unknown>) =>
     request<SystemConfigItem>("/admin/config", { method: "PUT", body: JSON.stringify(payload) }),
+  ssoConfig: () => request<{ userClientUrl: string }>("/admin/sso/config"),
+  saveSsoConfig: (userClientUrl: string) =>
+    request<{ userClientUrl: string }>("/admin/sso/config", {
+      method: "PUT",
+      body: JSON.stringify({ userClientUrl }),
+    }),
+  ssoClients: () => request<SsoClientItem[]>("/admin/sso/client/list"),
+  createSsoClient: (payload: { appId: string; name: string; redirectUris: string[]; status: number }) =>
+    request<SsoClientItem>("/admin/sso/client", { method: "POST", body: JSON.stringify(payload) }),
+  updateSsoClient: (id: number, payload: { name: string; redirectUris: string[]; status: number }) =>
+    request<SsoClientItem>(`/admin/sso/client/${id}`, { method: "PUT", body: JSON.stringify(payload) }),
+  rotateSsoClientSecret: (id: number) =>
+    request<{ clientId: number; clientSecret: string }>(`/admin/sso/client/${id}/secret/rotate`, {
+      method: "POST",
+      body: "{}",
+    }),
+  ssoIdentities: (query: { clientId?: number; keyword?: string; page?: number; pageSize?: number } = {}) =>
+    request<PageResult<SsoIdentityItem>>(`/admin/sso/identity/list${queryString(query)}`),
+  unlinkSsoIdentity: (id: number) => request<null>(`/admin/sso/identity/${id}`, { method: "DELETE" }),
+  ssoAudits: (query: { clientId?: number; auditStatus?: string; page?: number; pageSize?: number } = {}) =>
+    request<PageResult<SsoAuditItem>>(`/admin/sso/audit/list${queryString(query)}`),
   chats: (query: ChatRecordQuery = {}) => request<PageResult<ChatRecord>>(`/admin/chat/list${queryString(query)}`),
   chatDetail: (sessionId: number, query: { messagePage?: number; messagePageSize?: number } = {}) =>
     request<ChatDetail>(`/admin/chat/${sessionId}${queryString(query)}`),
diff --git a/ai_knowledge_base_v2/apps/admin-web/src/types/api.ts b/ai_knowledge_base_v2/apps/admin-web/src/types/api.ts
index 9ad18d0..4468c93 100644
--- a/ai_knowledge_base_v2/apps/admin-web/src/types/api.ts
+++ b/ai_knowledge_base_v2/apps/admin-web/src/types/api.ts
@@ -18,6 +18,46 @@ export interface AdminProfile {
   status: number;
 }
 
+export interface SsoClientItem {
+  id: number;
+  appId: string;
+  name: string;
+  redirectUris: string[];
+  status: number;
+  identityCount: number;
+  lastUsedAt?: string | null;
+  createdAt: string;
+  updatedAt: string;
+  clientSecret?: string;
+}
+
+export interface SsoIdentityItem {
+  id: number;
+  clientId: number;
+  clientName: string;
+  appId: string;
+  userId: number;
+  userName: string;
+  phone: string;
+  externalUserId: string;
+  displayNameSnapshot?: string | null;
+  lastLoginAt?: string | null;
+  createdAt: string;
+}
+
+export interface SsoAuditItem {
+  id: number;
+  appId?: string | null;
+  clientName?: string | null;
+  userId?: number | null;
+  externalUserId?: string | null;
+  action: string;
+  status: string;
+  errorMessage?: string | null;
+  ip?: string | null;
+  createdAt: string;
+}
+
 export interface DashboardStats {
   userCount: number;
   sessionCount: number;
diff --git a/ai_knowledge_base_v2/apps/backend/alembic/versions/0029_sso_integration.py b/ai_knowledge_base_v2/apps/backend/alembic/versions/0029_sso_integration.py
new file mode 100644
index 0000000..863015c
--- /dev/null
+++ b/ai_knowledge_base_v2/apps/backend/alembic/versions/0029_sso_integration.py
@@ -0,0 +1,77 @@
+"""add trusted application sso integration
+
+Revision ID: 0029_sso_integration
+Revises: 0028_chat_concurrency
+"""
+
+from __future__ import annotations
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = "0029_sso_integration"
+down_revision = "0028_chat_concurrency"
+branch_labels = None
+depends_on = None
+
+PRIMARY_KEY_TYPE = sa.BigInteger().with_variant(sa.Integer(), "sqlite")
+
+
+def upgrade() -> None:
+    op.create_table(
+        "sys_sso_client",
+        sa.Column("id", PRIMARY_KEY_TYPE, primary_key=True, autoincrement=True),
+        sa.Column("app_id", sa.String(length=80), nullable=False),
+        sa.Column("name", sa.String(length=100), nullable=False),
+        sa.Column("client_secret", sa.Text(), nullable=False),
+        sa.Column("redirect_uris", sa.Text(), nullable=False),
+        sa.Column("status", sa.Integer(), nullable=False, server_default="1"),
+        sa.Column("created_by", sa.BigInteger(), nullable=True),
+        sa.Column("last_used_at", sa.DateTime(), nullable=True),
+        sa.Column("created_at", sa.DateTime(), server_default=sa.func.now(), nullable=False),
+        sa.Column("updated_at", sa.DateTime(), server_default=sa.func.now(), nullable=False),
+    )
+    op.create_index("ix_sys_sso_client_app_id", "sys_sso_client", ["app_id"], unique=True)
+    op.create_index("ix_sys_sso_client_status", "sys_sso_client", ["status"])
+
+    op.create_table(
+        "sys_user_external_identity",
+        sa.Column("id", PRIMARY_KEY_TYPE, primary_key=True, autoincrement=True),
+        sa.Column("client_id", sa.BigInteger(), nullable=False),
+        sa.Column("user_id", sa.BigInteger(), nullable=False),
+        sa.Column("external_user_id", sa.String(length=120), nullable=False),
+        sa.Column("phone_snapshot", sa.String(length=20), nullable=True),
+        sa.Column("display_name_snapshot", sa.String(length=100), nullable=True),
+        sa.Column("last_login_at", sa.DateTime(), nullable=True),
+        sa.Column("created_at", sa.DateTime(), server_default=sa.func.now(), nullable=False),
+        sa.Column("updated_at", sa.DateTime(), server_default=sa.func.now(), nullable=False),
+        sa.ForeignKeyConstraint(["client_id"], ["sys_sso_client.id"]),
+        sa.ForeignKeyConstraint(["user_id"], ["sys_user.id"]),
+        sa.UniqueConstraint("client_id", "external_user_id", name="uq_sso_identity_client_external"),
+        sa.UniqueConstraint("client_id", "user_id", name="uq_sso_identity_client_user"),
+    )
+    op.create_index("ix_sys_user_external_identity_client_id", "sys_user_external_identity", ["client_id"])
+    op.create_index("ix_sso_identity_user", "sys_user_external_identity", ["user_id"])
+
+    op.create_table(
+        "sys_sso_login_audit",
+        sa.Column("id", PRIMARY_KEY_TYPE, primary_key=True, autoincrement=True),
+        sa.Column("client_id", sa.BigInteger(), nullable=True),
+        sa.Column("user_id", sa.BigInteger(), nullable=True),
+        sa.Column("external_user_id", sa.String(length=120), nullable=True),
+        sa.Column("action", sa.String(length=30), nullable=False),
+        sa.Column("status", sa.String(length=20), nullable=False),
+        sa.Column("error_message", sa.String(length=500), nullable=True),
+        sa.Column("ip", sa.String(length=50), nullable=True),
+        sa.Column("created_at", sa.DateTime(), server_default=sa.func.now(), nullable=False),
+    )
+    op.create_index("ix_sso_audit_client_created", "sys_sso_login_audit", ["client_id", "created_at"])
+    op.create_index("ix_sso_audit_user_created", "sys_sso_login_audit", ["user_id", "created_at"])
+    op.create_index("ix_sso_audit_status_created", "sys_sso_login_audit", ["status", "created_at"])
+
+
+def downgrade() -> None:
+    op.drop_table("sys_sso_login_audit")
+    op.drop_table("sys_user_external_identity")
+    op.drop_table("sys_sso_client")
diff --git a/ai_knowledge_base_v2/apps/backend/app/api/admin_sso.py b/ai_knowledge_base_v2/apps/backend/app/api/admin_sso.py
new file mode 100644
index 0000000..138175e
--- /dev/null
+++ b/ai_knowledge_base_v2/apps/backend/app/api/admin_sso.py
@@ -0,0 +1,305 @@
+from __future__ import annotations
+
+import json
+import secrets
+
+from fastapi import APIRouter, Depends, HTTPException, Query, status
+from sqlalchemy import delete, func, or_, select
+from sqlalchemy.orm import Session
+
+from app.api.pagination import page_result
+from app.core.database import get_db
+from app.core.dependencies import get_current_admin
+from app.core.responses import api_success
+from app.models.admin import Admin
+from app.models.ai_config import SystemConfig
+from app.models.sso import SsoClient, SsoLoginAudit, UserExternalIdentity
+from app.models.user import User
+from app.schemas.sso import SsoClientSaveRequest, SsoClientUpdateRequest, SsoPublicConfigRequest
+from app.services.admin_service import OperationLogService
+from app.services.secret_service import SecretService
+from app.services.sso_service import _json_list
+
+
+router = APIRouter()
+
+
+@router.get("/sso/config")
+def get_sso_config(
+    db: Session = Depends(get_db),
+    current_admin: Admin = Depends(get_current_admin),
+) -> dict:
+    value = db.scalar(
+        select(SystemConfig.config_value).where(SystemConfig.config_key == "sso_user_client_url")
+    )
+    return api_success({"userClientUrl": value or ""})
+
+
+@router.put("/sso/config")
+def save_sso_config(
+    payload: SsoPublicConfigRequest,
+    db: Session = Depends(get_db),
+    current_admin: Admin = Depends(get_current_admin),
+) -> dict:
+    config = db.scalar(
+        select(SystemConfig).where(SystemConfig.config_key == "sso_user_client_url")
+    )
+    if config is None:
+        config = SystemConfig(
+            config_key="sso_user_client_url",
+            config_value=payload.userClientUrl,
+            description="其他应用完成免登录后进入的千问千答用户端公网地址。",
+            updated_by=current_admin.id,
+        )
+        db.add(config)
+    else:
+        config.config_value = payload.userClientUrl
+        config.updated_by = current_admin.id
+    OperationLogService.write(
+        db,
+        admin_id=current_admin.id,
+        module="sso",
+        action="save_public_url",
+        target_id=config.id,
+    )
+    db.commit()
+    return api_success({"userClientUrl": payload.userClientUrl})
+
+
+@router.get("/sso/client/list")
+def list_sso_clients(
+    db: Session = Depends(get_db),
+    current_admin: Admin = Depends(get_current_admin),
+) -> dict:
+    identity_counts = (
+        select(
+            UserExternalIdentity.client_id.label("client_id"),
+            func.count(UserExternalIdentity.id).label("identity_count"),
+        )
+        .group_by(UserExternalIdentity.client_id)
+        .subquery()
+    )
+    rows = db.execute(
+        select(SsoClient, func.coalesce(identity_counts.c.identity_count, 0))
+        .outerjoin(identity_counts, identity_counts.c.client_id == SsoClient.id)
+        .order_by(SsoClient.created_at.desc(), SsoClient.id.desc())
+    ).all()
+    return api_success([_client_item(client, int(identity_count)) for client, identity_count in rows])
+
+
+@router.post("/sso/client")
+def create_sso_client(
+    payload: SsoClientSaveRequest,
+    db: Session = Depends(get_db),
+    current_admin: Admin = Depends(get_current_admin),
+) -> dict:
+    app_id = payload.appId.strip()
+    if db.scalar(select(SsoClient.id).where(SsoClient.app_id == app_id)) is not None:
+        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="应用ID已存在")
+    plaintext_secret = secrets.token_urlsafe(32)
+    client = SsoClient(
+        app_id=app_id,
+        name=payload.name.strip(),
+        client_secret=SecretService.encrypt(plaintext_secret),
+        redirect_uris=json.dumps(payload.redirectUris, ensure_ascii=False),
+        status=payload.status,
+        created_by=current_admin.id,
+    )
+    db.add(client)
+    db.flush()
+    OperationLogService.write(
+        db,
+        admin_id=current_admin.id,
+        module="sso",
+        action="create_client",
+        target_id=client.id,
+    )
+    db.commit()
+    db.refresh(client)
+    return api_success({**_client_item(client, 0), "clientSecret": plaintext_secret})
+
+
+@router.put("/sso/client/{client_id}")
+def update_sso_client(
+    client_id: int,
+    payload: SsoClientUpdateRequest,
+    db: Session = Depends(get_db),
+    current_admin: Admin = Depends(get_current_admin),
+) -> dict:
+    client = _require_client(db, client_id)
+    client.name = payload.name.strip()
+    client.redirect_uris = json.dumps(payload.redirectUris, ensure_ascii=False)
+    client.status = payload.status
+    OperationLogService.write(
+        db,
+        admin_id=current_admin.id,
+        module="sso",
+        action="update_client",
+        target_id=client.id,
+    )
+    db.commit()
+    identity_count = db.scalar(
+        select(func.count(UserExternalIdentity.id)).where(UserExternalIdentity.client_id == client.id)
+    ) or 0
+    return api_success(_client_item(client, identity_count))
+
+
+@router.post("/sso/client/{client_id}/secret/rotate")
+def rotate_sso_client_secret(
+    client_id: int,
+    db: Session = Depends(get_db),
+    current_admin: Admin = Depends(get_current_admin),
+) -> dict:
+    client = _require_client(db, client_id)
+    plaintext_secret = secrets.token_urlsafe(32)
+    client.client_secret = SecretService.encrypt(plaintext_secret)
+    OperationLogService.write(
+        db,
+        admin_id=current_admin.id,
+        module="sso",
+        action="rotate_secret",
+        target_id=client.id,
+    )
+    db.commit()
+    return api_success({"clientId": client.id, "clientSecret": plaintext_secret})
+
+
+@router.get("/sso/identity/list")
+def list_sso_identities(
+    clientId: int | None = Query(default=None, gt=0),
+    keyword: str = Query(default="", max_length=100),
+    page: int = Query(default=1, ge=1),
+    pageSize: int = Query(default=10, ge=10, le=100),
+    db: Session = Depends(get_db),
+    current_admin: Admin = Depends(get_current_admin),
+) -> dict:
+    filters = []
+    if clientId:
+        filters.append(UserExternalIdentity.client_id == clientId)
+    if keyword.strip():
+        value = f"%{keyword.strip()}%"
+        filters.append(
+            or_(
+                UserExternalIdentity.external_user_id.ilike(value),
+                User.phone.ilike(value),
+                User.name.ilike(value),
+                SsoClient.name.ilike(value),
+            )
+        )
+    total = db.scalar(
+        select(func.count(UserExternalIdentity.id))
+        .join(SsoClient, SsoClient.id == UserExternalIdentity.client_id)
+        .join(User, User.id == UserExternalIdentity.user_id)
+        .where(*filters)
+    ) or 0
+    rows = db.execute(
+        select(UserExternalIdentity, SsoClient, User)
+        .join(SsoClient, SsoClient.id == UserExternalIdentity.client_id)
+        .join(User, User.id == UserExternalIdentity.user_id)
+        .where(*filters)
+        .order_by(UserExternalIdentity.last_login_at.desc(), UserExternalIdentity.id.desc())
+        .offset((page - 1) * pageSize)
+        .limit(pageSize)
+    ).all()
+    items = [_identity_item(identity, client, user) for identity, client, user in rows]
+    return api_success(page_result(items, total=total, page=page, page_size=pageSize))
+
+
+@router.delete("/sso/identity/{identity_id}")
+def delete_sso_identity(
+    identity_id: int,
+    db: Session = Depends(get_db),
+    current_admin: Admin = Depends(get_current_admin),
+) -> dict:
+    identity = db.get(UserExternalIdentity, identity_id)
+    if identity is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="账号绑定不存在")
+    db.execute(delete(UserExternalIdentity).where(UserExternalIdentity.id == identity_id))
+    OperationLogService.write(
+        db,
+        admin_id=current_admin.id,
+        module="sso",
+        action="unlink_identity",
+        target_id=identity_id,
+    )
+    db.commit()
+    return api_success()
+
+
+@router.get("/sso/audit/list")
+def list_sso_audits(
+    clientId: int | None = Query(default=None, gt=0),
+    auditStatus: str = Query(default="", max_length=20),
+    page: int = Query(default=1, ge=1),
+    pageSize: int = Query(default=10, ge=10, le=100),
+    db: Session = Depends(get_db),
+    current_admin: Admin = Depends(get_current_admin),
+) -> dict:
+    filters = []
+    if clientId:
+        filters.append(SsoLoginAudit.client_id == clientId)
+    if auditStatus:
+        filters.append(SsoLoginAudit.status == auditStatus.upper())
+    total = db.scalar(select(func.count(SsoLoginAudit.id)).where(*filters)) or 0
+    rows = db.execute(
+        select(SsoLoginAudit, SsoClient)
+        .outerjoin(SsoClient, SsoClient.id == SsoLoginAudit.client_id)
+        .where(*filters)
+        .order_by(SsoLoginAudit.created_at.desc(), SsoLoginAudit.id.desc())
+        .offset((page - 1) * pageSize)
+        .limit(pageSize)
+    ).all()
+    items = [_audit_item(audit, client) for audit, client in rows]
+    return api_success(page_result(items, total=total, page=page, page_size=pageSize))
+
+
+def _require_client(db: Session, client_id: int) -> SsoClient:
+    client = db.get(SsoClient, client_id)
+    if client is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="接入应用不存在")
+    return client
+
+
+def _client_item(client: SsoClient, identity_count: int) -> dict:
+    return {
+        "id": client.id,
+        "appId": client.app_id,
+        "name": client.name,
+        "redirectUris": _json_list(client.redirect_uris),
+        "status": client.status,
+        "identityCount": identity_count,
+        "lastUsedAt": client.last_used_at,
+        "createdAt": client.created_at,
+        "updatedAt": client.updated_at,
+    }
+
+
+def _identity_item(identity: UserExternalIdentity, client: SsoClient, user: User) -> dict:
+    return {
+        "id": identity.id,
+        "clientId": client.id,
+        "clientName": client.name,
+        "appId": client.app_id,
+        "userId": user.id,
+        "userName": user.name,
+        "phone": user.phone,
+        "externalUserId": identity.external_user_id,
+        "displayNameSnapshot": identity.display_name_snapshot,
+        "lastLoginAt": identity.last_login_at,
+        "createdAt": identity.created_at,
+    }
+
+
+def _audit_item(audit: SsoLoginAudit, client: SsoClient | None) -> dict:
+    return {
+        "id": audit.id,
+        "appId": client.app_id if client else None,
+        "clientName": client.name if client else None,
+        "userId": audit.user_id,
+        "externalUserId": audit.external_user_id,
+        "action": audit.action,
+        "status": audit.status,
+        "errorMessage": audit.error_message,
+        "ip": audit.ip,
+        "createdAt": audit.created_at,
+    }
diff --git a/ai_knowledge_base_v2/apps/backend/app/api/auth.py b/ai_knowledge_base_v2/apps/backend/app/api/auth.py
index d1c5042..175bb7e 100644
--- a/ai_knowledge_base_v2/apps/backend/app/api/auth.py
+++ b/ai_knowledge_base_v2/apps/backend/app/api/auth.py
@@ -7,9 +7,11 @@ from app.core.database import get_db
 from app.core.dependencies import get_current_token_payload
 from app.core.responses import api_success
 from app.schemas.auth import CaptchaResponse, LoginRequest, LoginResponse, SendSmsRequest
+from app.schemas.sso import SsoExchangeRequest
 from app.services.auth_service import AuthService
 from app.services.captcha_service import CaptchaService
 from app.services.security_state_service import client_ip
+from app.services.sso_service import SsoService
 
 router = APIRouter()
 
@@ -31,6 +33,12 @@ def login(payload: LoginRequest, db: Session = Depends(get_db)) -> dict:
     return api_success(LoginResponse.model_validate(result).model_dump(mode="json"))
 
 
+@router.post("/sso/exchange")
+def exchange_sso(payload: SsoExchangeRequest, request: Request, db: Session = Depends(get_db)) -> dict:
+    result = SsoService.exchange(db, code=payload.code, ip=client_ip(request))
+    return api_success(LoginResponse.model_validate(result).model_dump(mode="json"))
+
+
 @router.post("/logout")
 def logout(token_payload: dict = Depends(get_current_token_payload)) -> dict:
     AuthService.logout(token_payload)
diff --git a/ai_knowledge_base_v2/apps/backend/app/api/integration_sso.py b/ai_knowledge_base_v2/apps/backend/app/api/integration_sso.py
new file mode 100644
index 0000000..b54e6e0
--- /dev/null
+++ b/ai_knowledge_base_v2/apps/backend/app/api/integration_sso.py
@@ -0,0 +1,43 @@
+from __future__ import annotations
+
+from fastapi import APIRouter, Depends, HTTPException, Request, status
+from pydantic import ValidationError
+from sqlalchemy.orm import Session
+
+from app.core.database import get_db
+from app.core.responses import api_success
+from app.schemas.sso import SsoTicketRequest
+from app.services.security_state_service import client_ip
+from app.services.sso_service import SsoService
+
+
+router = APIRouter()
+
+
+@router.post("/ticket")
+async def create_ticket(request: Request, db: Session = Depends(get_db)) -> dict:
+    raw_body = await request.body()
+    try:
+        payload = SsoTicketRequest.model_validate_json(raw_body)
+    except ValidationError as exc:
+        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail="接入用户参数不完整") from exc
+
+    app_id = request.headers.get("X-App-Id", "").strip()
+    timestamp = request.headers.get("X-Timestamp", "").strip()
+    nonce = request.headers.get("X-Nonce", "").strip()
+    signature = request.headers.get("X-Signature", "").strip()
+    if not all((app_id, timestamp, nonce, signature)):
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="缺少应用签名信息")
+
+    return api_success(
+        SsoService.issue_ticket(
+            db,
+            app_id=app_id,
+            timestamp=timestamp,
+            nonce=nonce,
+            signature=signature,
+            raw_body=raw_body,
+            payload=payload,
+            ip=client_ip(request),
+        )
+    )
diff --git a/ai_knowledge_base_v2/apps/backend/app/api/router.py b/ai_knowledge_base_v2/apps/backend/app/api/router.py
index 76a5036..b89d879 100644
--- a/ai_knowledge_base_v2/apps/backend/app/api/router.py
+++ b/ai_knowledge_base_v2/apps/backend/app/api/router.py
@@ -12,16 +12,19 @@ from app.api import (
     admin_knowledge_lifecycle,
     admin_records,
     admin_settings,
+    admin_sso,
     admin_users,
     auth,
     chat,
     health,
+    integration_sso,
     user,
 )
 
 api_router = APIRouter()
 api_router.include_router(health.router, tags=["health"])
 api_router.include_router(auth.router, prefix="/auth", tags=["auth"])
+api_router.include_router(integration_sso.router, prefix="/integration/sso", tags=["integration-sso"])
 api_router.include_router(user.router, prefix="/user", tags=["user"])
 api_router.include_router(chat.router, prefix="/chat", tags=["chat"])
 api_router.include_router(admin_auth.router, prefix="/admin", tags=["admin"])
@@ -33,4 +36,5 @@ api_router.include_router(admin_users.router, prefix="/admin", tags=["admin"])
 api_router.include_router(admin_knowledge.router, prefix="/admin", tags=["admin"])
 api_router.include_router(admin_knowledge_lifecycle.router, prefix="/admin", tags=["admin-knowledge-lifecycle"])
 api_router.include_router(admin_settings.router, prefix="/admin", tags=["admin"])
+api_router.include_router(admin_sso.router, prefix="/admin", tags=["admin-sso"])
 api_router.include_router(admin_records.router, prefix="/admin", tags=["admin"])
diff --git a/ai_knowledge_base_v2/apps/backend/app/models/__init__.py b/ai_knowledge_base_v2/apps/backend/app/models/__init__.py
index a56f3c2..2f959bc 100644
--- a/ai_knowledge_base_v2/apps/backend/app/models/__init__.py
+++ b/ai_knowledge_base_v2/apps/backend/app/models/__init__.py
@@ -23,6 +23,7 @@ from app.models.knowledge import (
     UserKnowledgePermission,
 )
 from app.models.logs import AiRequestLog, LogRetentionPolicy, OperationLog, StorageSnapshot
+from app.models.sso import SsoClient, SsoLoginAudit, UserExternalIdentity
 from app.models.user import User
 
 __all__ = [
@@ -53,6 +54,8 @@ __all__ = [
     "PeriodicReport",
     "LogRetentionPolicy",
     "StorageSnapshot",
+    "SsoClient",
+    "SsoLoginAudit",
     "TopicSession",
     "TopicSummary",
     "Prompt",
@@ -62,6 +65,7 @@ __all__ = [
     "ShareDraft",
     "TeacherHelpCard",
     "User",
+    "UserExternalIdentity",
     "UserEntitlement",
     "UserEntitlementLog",
     "UserGrowthProfile",
diff --git a/ai_knowledge_base_v2/apps/backend/app/models/sso.py b/ai_knowledge_base_v2/apps/backend/app/models/sso.py
new file mode 100644
index 0000000..fd7268f
--- /dev/null
+++ b/ai_knowledge_base_v2/apps/backend/app/models/sso.py
@@ -0,0 +1,75 @@
+from __future__ import annotations
+
+from datetime import datetime
+
+from sqlalchemy import BigInteger, DateTime, ForeignKey, Index, Integer, String, Text, UniqueConstraint, func
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.models.base import Base
+
+
+PRIMARY_KEY_TYPE = BigInteger().with_variant(Integer, "sqlite")
+
+
+class SsoClient(Base):
+    __tablename__ = "sys_sso_client"
+    __table_args__ = (Index("ix_sys_sso_client_status", "status"),)
+
+    id: Mapped[int] = mapped_column(PRIMARY_KEY_TYPE, primary_key=True, autoincrement=True)
+    app_id: Mapped[str] = mapped_column(String(80), unique=True, index=True, nullable=False)
+    name: Mapped[str] = mapped_column(String(100), nullable=False)
+    client_secret: Mapped[str] = mapped_column(Text, nullable=False)
+    redirect_uris: Mapped[str] = mapped_column(Text, default="[]", nullable=False)
+    status: Mapped[int] = mapped_column(Integer, default=1, nullable=False)
+    created_by: Mapped[int | None] = mapped_column(BigInteger, nullable=True)
+    last_used_at: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)
+    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now(), nullable=False)
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime,
+        server_default=func.now(),
+        onupdate=func.now(),
+        nullable=False,
+    )
+
+
+class UserExternalIdentity(Base):
+    __tablename__ = "sys_user_external_identity"
+    __table_args__ = (
+        UniqueConstraint("client_id", "external_user_id", name="uq_sso_identity_client_external"),
+        UniqueConstraint("client_id", "user_id", name="uq_sso_identity_client_user"),
+        Index("ix_sso_identity_user", "user_id"),
+    )
+
+    id: Mapped[int] = mapped_column(PRIMARY_KEY_TYPE, primary_key=True, autoincrement=True)
+    client_id: Mapped[int] = mapped_column(ForeignKey("sys_sso_client.id"), index=True, nullable=False)
+    user_id: Mapped[int] = mapped_column(ForeignKey("sys_user.id"), nullable=False)
+    external_user_id: Mapped[str] = mapped_column(String(120), nullable=False)
+    phone_snapshot: Mapped[str | None] = mapped_column(String(20), nullable=True)
+    display_name_snapshot: Mapped[str | None] = mapped_column(String(100), nullable=True)
+    last_login_at: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)
+    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now(), nullable=False)
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime,
+        server_default=func.now(),
+        onupdate=func.now(),
+        nullable=False,
+    )
+
+
+class SsoLoginAudit(Base):
+    __tablename__ = "sys_sso_login_audit"
+    __table_args__ = (
+        Index("ix_sso_audit_client_created", "client_id", "created_at"),
+        Index("ix_sso_audit_user_created", "user_id", "created_at"),
+        Index("ix_sso_audit_status_created", "status", "created_at"),
+    )
+
+    id: Mapped[int] = mapped_column(PRIMARY_KEY_TYPE, primary_key=True, autoincrement=True)
+    client_id: Mapped[int | None] = mapped_column(BigInteger, nullable=True)
+    user_id: Mapped[int | None] = mapped_column(BigInteger, nullable=True)
+    external_user_id: Mapped[str | None] = mapped_column(String(120), nullable=True)
+    action: Mapped[str] = mapped_column(String(30), nullable=False)
+    status: Mapped[str] = mapped_column(String(20), nullable=False)
+    error_message: Mapped[str | None] = mapped_column(String(500), nullable=True)
+    ip: Mapped[str | None] = mapped_column(String(50), nullable=True)
+    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now(), nullable=False)
diff --git a/ai_knowledge_base_v2/apps/backend/app/schemas/auth.py b/ai_knowledge_base_v2/apps/backend/app/schemas/auth.py
index c3bc6fa..d05e276 100644
--- a/ai_knowledge_base_v2/apps/backend/app/schemas/auth.py
+++ b/ai_knowledge_base_v2/apps/backend/app/schemas/auth.py
@@ -22,6 +22,7 @@ class LoginResponse(BaseModel):
     token: str
     expiredAt: datetime
     user: UserProfile
+    returnUrl: str | None = None
 
 
 class CaptchaResponse(BaseModel):
diff --git a/ai_knowledge_base_v2/apps/backend/app/schemas/sso.py b/ai_knowledge_base_v2/apps/backend/app/schemas/sso.py
new file mode 100644
index 0000000..907fd9c
--- /dev/null
+++ b/ai_knowledge_base_v2/apps/backend/app/schemas/sso.py
@@ -0,0 +1,99 @@
+from __future__ import annotations
+
+from datetime import datetime
+
+from pydantic import BaseModel, Field, field_validator
+
+
+class SsoTicketRequest(BaseModel):
+    externalUserId: str = Field(min_length=1, max_length=120)
+    verifiedPhone: str | None = Field(default=None, min_length=11, max_length=20)
+    displayName: str | None = Field(default=None, max_length=100)
+    returnUrl: str | None = Field(default=None, max_length=1000)
+
+
+class SsoExchangeRequest(BaseModel):
+    code: str = Field(min_length=20, max_length=200)
+
+
+class SsoClientSaveRequest(BaseModel):
+    appId: str = Field(min_length=3, max_length=80, pattern=r"^[A-Za-z0-9][A-Za-z0-9._-]+$")
+    name: str = Field(min_length=1, max_length=100)
+    redirectUris: list[str] = Field(default_factory=list, max_length=20)
+    status: int = Field(default=1, ge=0, le=1)
+
+    @field_validator("redirectUris")
+    @classmethod
+    def validate_redirect_uris(cls, values: list[str]) -> list[str]:
+        cleaned: list[str] = []
+        for raw in values:
+            value = raw.strip()
+            if not value:
+                continue
+            if not value.startswith(("https://", "http://localhost", "http://127.0.0.1")):
+                raise ValueError("回跳地址必须使用 HTTPS；本地调试可使用 localhost 或 127.0.0.1")
+            if value not in cleaned:
+                cleaned.append(value)
+        return cleaned
+
+
+class SsoClientUpdateRequest(BaseModel):
+    name: str = Field(min_length=1, max_length=100)
+    redirectUris: list[str] = Field(default_factory=list, max_length=20)
+    status: int = Field(default=1, ge=0, le=1)
+
+    @field_validator("redirectUris")
+    @classmethod
+    def validate_redirect_uris(cls, values: list[str]) -> list[str]:
+        return SsoClientSaveRequest.validate_redirect_uris(values)
+
+
+class SsoPublicConfigRequest(BaseModel):
+    userClientUrl: str = Field(default="", max_length=1000)
+
+    @field_validator("userClientUrl")
+    @classmethod
+    def validate_user_client_url(cls, value: str) -> str:
+        cleaned = value.strip().rstrip("/")
+        if cleaned and not cleaned.startswith(("https://", "http://localhost", "http://127.0.0.1")):
+            raise ValueError("用户端公网地址必须使用 HTTPS；本地调试可使用 localhost 或 127.0.0.1")
+        return cleaned
+
+
+class SsoClientItem(BaseModel):
+    id: int
+    appId: str
+    name: str
+    redirectUris: list[str]
+    status: int
+    identityCount: int
+    lastUsedAt: datetime | None = None
+    createdAt: datetime
+    updatedAt: datetime
+
+
+class SsoIdentityItem(BaseModel):
+    id: int
+    clientId: int
+    clientName: str
+    appId: str
+    userId: int
+    userName: str
+    phone: str
+    externalUserId: str
+    displayNameSnapshot: str | None = None
+    lastLoginAt: datetime | None = None
+    createdAt: datetime
+
+
+class SsoAuditItem(BaseModel):
+    id: int
+    appId: str | None = None
+    clientName: str | None = None
+    userId: int | None = None
+    externalUserId: str | None = None
+    action: str
+    status: str
+    errorMessage: str | None = None
+    ip: str | None = None
+    createdAt: datetime
diff --git a/ai_knowledge_base_v2/apps/backend/app/services/auth_service.py b/ai_knowledge_base_v2/apps/backend/app/services/auth_service.py
index a275b30..e8d2c17 100644
--- a/ai_knowledge_base_v2/apps/backend/app/services/auth_service.py
+++ b/ai_knowledge_base_v2/apps/backend/app/services/auth_service.py
@@ -26,7 +26,7 @@ class AuthService:
         ip: str,
     ) -> None:
         user = cls._get_existing_user(db, phone)
-        cls._ensure_user_can_login(user)
+        cls.ensure_user_can_login(user)
         captcha_key = cls._captcha_required_key(phone)
         has_captcha = bool(captcha_id or captcha_code)
         if has_captcha:
@@ -65,7 +65,7 @@ class AuthService:
             raise
         SecurityStateService.clear(failure_key)
         user = cls._get_existing_user(db, phone)
-        cls._ensure_user_can_login(user)
+        cls.ensure_user_can_login(user)
 
         now = datetime.now(UTC).replace(tzinfo=None)
         user.last_login_at = now
@@ -96,7 +96,7 @@ class AuthService:
         raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="手机号不在学员名单中，请联系管理员")
 
     @staticmethod
-    def _ensure_user_can_login(user: User) -> None:
+    def ensure_user_can_login(user: User) -> None:
         now = datetime.now(UTC).replace(tzinfo=None)
         if user.status != 1:
             raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="账号已禁用")
diff --git a/ai_knowledge_base_v2/apps/backend/app/services/sso_service.py b/ai_knowledge_base_v2/apps/backend/app/services/sso_service.py
new file mode 100644
index 0000000..2ff5767
--- /dev/null
+++ b/ai_knowledge_base_v2/apps/backend/app/services/sso_service.py
@@ -0,0 +1,387 @@
+from __future__ import annotations
+
+from datetime import datetime
+import hashlib
+import hmac
+import json
+import secrets
+import time
+from urllib.parse import quote
+
+from fastapi import HTTPException, status
+from sqlalchemy import func, select
+from sqlalchemy.orm import Session
+
+from app.core.security import create_access_token
+from app.models.ai_config import SystemConfig
+from app.models.sso import SsoClient, SsoLoginAudit, UserExternalIdentity
+from app.models.user import User
+from app.schemas.sso import SsoTicketRequest
+from app.services.auth_service import AuthService
+from app.services.redis_client import get_sync_redis_client
+from app.services.security_state_service import SecurityStateService
+from app.services.secret_service import SecretService
+
+
+class SsoService:
+    CODE_TTL_SECONDS = 60
+    SIGNATURE_WINDOW_SECONDS = 300
+    CODE_NAMESPACE = "auth:sso:code"
+    NONCE_NAMESPACE = "auth:sso:nonce"
+
+    @classmethod
+    def issue_ticket(
+        cls,
+        db: Session,
+        *,
+        app_id: str,
+        timestamp: str,
+        nonce: str,
+        signature: str,
+        raw_body: bytes,
+        payload: SsoTicketRequest,
+        ip: str,
+    ) -> dict:
+        client = db.scalar(
+            select(SsoClient).where(SsoClient.app_id == app_id).with_for_update()
+        )
+        if client is None or client.status != 1:
+            raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="接入应用不存在或已停用")
+
+        try:
+            cls._verify_request(client, timestamp, nonce, signature, raw_body)
+            cls._reserve_nonce(client, nonce)
+            SecurityStateService.enforce_limit(
+                f"rate:sso:ticket:{client.id}",
+                limit=600,
+                window_seconds=60,
+                message="该应用免登录请求过于频繁，请稍后再试",
+            )
+            identity, user = cls._resolve_identity(db, client, payload)
+            cls._validate_return_url(client, payload.returnUrl)
+            AuthService.ensure_user_can_login(user)
+
+            now = _db_now(db)
+            client.last_used_at = now
+            identity.phone_snapshot = payload.verifiedPhone or identity.phone_snapshot
+            identity.display_name_snapshot = payload.displayName or identity.display_name_snapshot
+            db.add(
+                SsoLoginAudit(
+                    client_id=client.id,
+                    user_id=user.id,
+                    external_user_id=payload.externalUserId,
+                    action="ticket",
+                    status="SUCCESS",
+                    ip=ip,
+                )
+            )
+            db.commit()
+
+            code = cls._store_ticket(
+                {
+                    "clientId": client.id,
+                    "userId": user.id,
+                    "identityId": identity.id,
+                    "externalUserId": payload.externalUserId,
+                    "returnUrl": payload.returnUrl,
+                    "issuedAt": int(time.time()),
+                }
+            )
+            return {
+                "code": code,
+                "expiresInSeconds": cls.CODE_TTL_SECONDS,
+                "entryUrl": cls._entry_url(db, code),
+            }
+        except HTTPException as exc:
+            cls.record_failure(
+                db,
+                client_id=client.id,
+                external_user_id=payload.externalUserId,
+                action="ticket",
+                error_message=str(exc.detail),
+                ip=ip,
+            )
+            raise
+        except Exception as exc:
+            cls.record_failure(
+                db,
+                client_id=client.id,
+                external_user_id=payload.externalUserId,
+                action="ticket",
+                error_message="单点登录服务暂时不可用",
+                ip=ip,
+            )
+            raise HTTPException(
+                status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
+                detail="单点登录服务暂时不可用",
+            ) from exc
+
+    @classmethod
+    def exchange(cls, db: Session, *, code: str, ip: str) -> dict:
+        try:
+            ticket = cls._consume_ticket(code)
+        except HTTPException as exc:
+            cls.record_failure(
+                db,
+                client_id=None,
+                action="exchange",
+                error_message=str(exc.detail),
+                ip=ip,
+            )
+            raise
+        client_id = _int_value(ticket.get("clientId"))
+        user_id = _int_value(ticket.get("userId"))
+        identity_id = _int_value(ticket.get("identityId"))
+        external_user_id = str(ticket.get("externalUserId") or "")
+
+        try:
+            client = db.get(SsoClient, client_id)
+            identity = db.get(UserExternalIdentity, identity_id)
+            user = db.get(User, user_id)
+            if client is None or client.status != 1:
+                raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="接入应用已停用")
+            if (
+                identity is None
+                or identity.client_id != client.id
+                or identity.user_id != user_id
+                or identity.external_user_id != external_user_id
+            ):
+                raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="外部账号绑定已失效")
+            if user is None or user.is_deleted:
+                raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="用户不存在")
+            AuthService.ensure_user_can_login(user)
+
+            now = _db_now(db)
+            identity.last_login_at = now
+            user.last_login_at = now
+            db.add(
+                SsoLoginAudit(
+                    client_id=client.id,
+                    user_id=user.id,
+                    external_user_id=external_user_id,
+                    action="exchange",
+                    status="SUCCESS",
+                    ip=ip,
+                )
+            )
+            db.commit()
+            db.refresh(user)
+            token, expired_at = create_access_token(str(user.id), "user")
+            return {
+                "token": token,
+                "expiredAt": expired_at,
+                "user": user,
+                "returnUrl": ticket.get("returnUrl"),
+            }
+        except HTTPException as exc:
+            cls.record_failure(
+                db,
+                client_id=client_id or None,
+                user_id=user_id or None,
+                external_user_id=external_user_id,
+                action="exchange",
+                error_message=str(exc.detail),
+                ip=ip,
+            )
+            raise
+
+    @classmethod
+    def record_failure(
+        cls,
+        db: Session,
+        *,
+        client_id: int | None,
+        action: str,
+        error_message: str,
+        ip: str,
+        user_id: int | None = None,
+        external_user_id: str | None = None,
+    ) -> None:
+        db.rollback()
+        db.add(
+            SsoLoginAudit(
+                client_id=client_id,
+                user_id=user_id,
+                external_user_id=external_user_id,
+                action=action,
+                status="FAILED",
+                error_message=error_message[:500],
+                ip=ip,
+            )
+        )
+        db.commit()
+
+    @classmethod
+    def _verify_request(
+        cls,
+        client: SsoClient,
+        timestamp: str,
+        nonce: str,
+        signature: str,
+        raw_body: bytes,
+    ) -> None:
+        try:
+            request_time = int(timestamp)
+        except (TypeError, ValueError) as exc:
+            raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="应用时间戳无效") from exc
+        if abs(int(time.time()) - request_time) > cls.SIGNATURE_WINDOW_SECONDS:
+            raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="应用请求已过期")
+        if not 16 <= len(nonce) <= 120:
+            raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="应用随机数无效")
+
+        body_hash = hashlib.sha256(raw_body).hexdigest()
+        canonical = f"{timestamp}\n{nonce}\n{body_hash}".encode("utf-8")
+        secret = SecretService.decrypt(client.client_secret).encode("utf-8")
+        expected = hmac.new(secret, canonical, hashlib.sha256).hexdigest()
+        if not hmac.compare_digest(expected, signature.lower()):
+            raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="应用签名无效")
+
+    @classmethod
+    def _reserve_nonce(cls, client: SsoClient, nonce: str) -> None:
+        redis = cls._required_redis()
+        key = f"{cls.NONCE_NAMESPACE}:{client.id}:{hashlib.sha256(nonce.encode()).hexdigest()}"
+        try:
+            reserved = redis.set(key, "1", ex=cls.SIGNATURE_WINDOW_SECONDS, nx=True)
+        except Exception as exc:
+            raise HTTPException(
+                status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
+                detail="单点登录服务暂时不可用",
+            ) from exc
+        if not reserved:
+            raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="应用请求已被使用")
+
+    @classmethod
+    def _resolve_identity(
+        cls,
+        db: Session,
+        client: SsoClient,
+        payload: SsoTicketRequest,
+    ) -> tuple[UserExternalIdentity, User]:
+        identity = db.scalar(
+            select(UserExternalIdentity).where(
+                UserExternalIdentity.client_id == client.id,
+                UserExternalIdentity.external_user_id == payload.externalUserId,
+            )
+        )
+        if identity is not None:
+            user = db.get(User, identity.user_id)
+            if user is None or user.is_deleted:
+                raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="绑定的学员账号不存在")
+            return identity, user
+
+        if not payload.verifiedPhone:
+            raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="首次登录必须提供已验证手机号")
+        user = db.scalar(
+            select(User).where(User.phone == payload.verifiedPhone, User.is_deleted == 0)
+        )
+        if user is None:
+            raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="手机号不在学员名单中")
+        existing_user_binding = db.scalar(
+            select(UserExternalIdentity).where(
+                UserExternalIdentity.client_id == client.id,
+                UserExternalIdentity.user_id == user.id,
+            )
+        )
+        if existing_user_binding is not None:
+            raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="该学员已绑定其他外部账号")
+
+        identity = UserExternalIdentity(
+            client_id=client.id,
+            user_id=user.id,
+            external_user_id=payload.externalUserId,
+            phone_snapshot=payload.verifiedPhone,
+            display_name_snapshot=payload.displayName,
+        )
+        db.add(identity)
+        db.flush()
+        return identity, user
+
+    @staticmethod
+    def _validate_return_url(client: SsoClient, return_url: str | None) -> None:
+        if not return_url:
+            return
+        allowed = _json_list(client.redirect_uris)
+        if return_url.rstrip("/") not in {item.rstrip("/") for item in allowed}:
+            raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="回跳地址不在应用白名单中")
+
+    @classmethod
+    def _store_ticket(cls, payload: dict) -> str:
+        redis = cls._required_redis()
+        for _ in range(3):
+            code = secrets.token_urlsafe(32)
+            key = cls._code_key(code)
+            try:
+                stored = redis.set(
+                    key,
+                    json.dumps(payload, ensure_ascii=False, separators=(",", ":")),
+                    ex=cls.CODE_TTL_SECONDS,
+                    nx=True,
+                )
+            except Exception as exc:
+                raise HTTPException(
+                    status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
+                    detail="单点登录服务暂时不可用",
+                ) from exc
+            if stored:
+                return code
+        raise HTTPException(status_code=status.HTTP_503_SERVICE_UNAVAILABLE, detail="授权码生成失败")
+
+    @classmethod
+    def _consume_ticket(cls, code: str) -> dict:
+        redis = cls._required_redis()
+        key = cls._code_key(code)
+        try:
+            raw = redis.eval(
+                "local v=redis.call('GET',KEYS[1]); if v then redis.call('DEL',KEYS[1]) end; return v",
+                1,
+                key,
+            )
+        except Exception as exc:
+            raise HTTPException(
+                status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
+                detail="单点登录服务暂时不可用",
+            ) from exc
+        if not raw:
+            raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="授权码无效、已使用或已过期")
+        try:
+            payload = json.loads(raw)
+        except (TypeError, json.JSONDecodeError) as exc:
+            raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="授权码数据无效") from exc
+        return payload
+
+    @staticmethod
+    def _required_redis():
+        redis = get_sync_redis_client()
+        if redis is None:
+            raise HTTPException(status_code=status.HTTP_503_SERVICE_UNAVAILABLE, detail="单点登录服务暂时不可用")
+        return redis
+
+    @classmethod
+    def _code_key(cls, code: str) -> str:
+        return f"{cls.CODE_NAMESPACE}:{hashlib.sha256(code.encode()).hexdigest()}"
+
+    @staticmethod
+    def _entry_url(db: Session, code: str) -> str:
+        value = db.scalar(select(SystemConfig.config_value).where(SystemConfig.config_key == "sso_user_client_url"))
+        base = (value or "").strip().rstrip("/")
+        path = f"/?sso_code={quote(code)}"
+        return f"{base}{path}" if base else path
+
+
+def _json_list(value: str | None) -> list[str]:
+    try:
+        decoded = json.loads(value or "[]")
+    except json.JSONDecodeError:
+        return []
+    return [str(item) for item in decoded if str(item).strip()] if isinstance(decoded, list) else []
+
+
+def _db_now(db: Session) -> datetime:
+    return db.scalar(select(func.now())) or datetime.now()
+
+
+def _int_value(value) -> int:
+    try:
+        return int(value)
+    except (TypeError, ValueError):
+        return 0
diff --git a/ai_knowledge_base_v2/apps/backend/tests/test_sso_service.py b/ai_knowledge_base_v2/apps/backend/tests/test_sso_service.py
new file mode 100644
index 0000000..205d8bb
--- /dev/null
+++ b/ai_knowledge_base_v2/apps/backend/tests/test_sso_service.py
@@ -0,0 +1,213 @@
+from __future__ import annotations
+
+import hashlib
+import hmac
+import json
+import secrets
+import time
+
+from fastapi import HTTPException
+import pytest
+from sqlalchemy import create_engine, func, select
+from sqlalchemy.orm import Session
+from sqlalchemy.pool import StaticPool
+
+from app.models import Base
+from app.core.config import get_settings
+from app.models.ai_config import SystemConfig
+from app.models.sso import SsoClient, SsoLoginAudit, UserExternalIdentity
+from app.models.user import User
+from app.schemas.sso import SsoTicketRequest
+from app.services.secret_service import SecretService
+from app.services.sso_service import SsoService
+
+
+class FakeRedis:
+    def __init__(self):
+        self.values: dict[str, str] = {}
+
+    def set(self, key: str, value: str, *, ex: int, nx: bool = False):
+        if nx and key in self.values:
+            return False
+        self.values[key] = value
+        return True
+
+    def eval(self, _script: str, _key_count: int, key: str):
+        return self.values.pop(key, None)
+
+
+def _db() -> Session:
+    engine = create_engine(
+        "sqlite:///:memory:",
+        connect_args={"check_same_thread": False},
+        poolclass=StaticPool,
+    )
+    Base.metadata.create_all(engine)
+    return Session(engine)
+
+
+def _signature(secret: str, timestamp: str, nonce: str, body: bytes) -> str:
+    body_hash = hashlib.sha256(body).hexdigest()
+    canonical = f"{timestamp}\n{nonce}\n{body_hash}".encode()
+    return hmac.new(secret.encode(), canonical, hashlib.sha256).hexdigest()
+
+
+def _seed(db: Session) -> tuple[User, SsoClient, str]:
+    secret = "integration-secret"
+    user = User(
+        id=1,
+        phone="13800138000",
+        name="测试学员",
+        status=1,
+        daily_chat_limit=100,
+        daily_chat_used=0,
+        is_deleted=0,
+    )
+    client = SsoClient(
+        id=1,
+        app_id="student-app",
+        name="学员应用",
+        client_secret=SecretService.encrypt(secret),
+        redirect_uris='["https://student.example.com/home"]',
+        status=1,
+    )
+    db.add_all(
+        [
+            user,
+            client,
+            SystemConfig(config_key="sso_user_client_url", config_value="https://qa.example.com"),
+        ]
+    )
+    db.commit()
+    return user, client, secret
+
+
+def test_sso_ticket_binds_user_and_exchanges_only_once(monkeypatch: pytest.MonkeyPatch):
+    redis = FakeRedis()
+    monkeypatch.setattr("app.services.sso_service.get_sync_redis_client", lambda: redis)
+    monkeypatch.setattr(get_settings(), "jwt_secret_key", "test-sso-jwt-secret-key-32-bytes-long")
+    with _db() as db:
+        user, client, secret = _seed(db)
+        raw_body = json.dumps(
+            {
+                "externalUserId": "external-1001",
+                "verifiedPhone": user.phone,
+                "displayName": "外部昵称",
+                "returnUrl": "https://student.example.com/home",
+            },
+            ensure_ascii=False,
+            separators=(",", ":"),
+        ).encode()
+        payload = SsoTicketRequest.model_validate_json(raw_body)
+        timestamp = str(int(time.time()))
+        nonce = secrets.token_urlsafe(24)
+
+        result = SsoService.issue_ticket(
+            db,
+            app_id=client.app_id,
+            timestamp=timestamp,
+            nonce=nonce,
+            signature=_signature(secret, timestamp, nonce, raw_body),
+            raw_body=raw_body,
+            payload=payload,
+            ip="127.0.0.1",
+        )
+
+        assert result["entryUrl"].startswith("https://qa.example.com/?sso_code=")
+        assert db.scalar(select(func.count(UserExternalIdentity.id))) == 1
+
+        login = SsoService.exchange(db, code=result["code"], ip="127.0.0.1")
+        assert login["user"].id == user.id
+        assert login["returnUrl"] == "https://student.example.com/home"
+        assert login["token"]
+
+        with pytest.raises(HTTPException) as reused:
+            SsoService.exchange(db, code=result["code"], ip="127.0.0.1")
+        assert reused.value.status_code == 401
+        assert db.scalar(select(func.count(SsoLoginAudit.id))) == 3
+
+
+def test_sso_rejects_replayed_nonce_and_unlisted_return_url(monkeypatch: pytest.MonkeyPatch):
+    redis = FakeRedis()
+    monkeypatch.setattr("app.services.sso_service.get_sync_redis_client", lambda: redis)
+    with _db() as db:
+        user, client, secret = _seed(db)
+        timestamp = str(int(time.time()))
+        nonce = "nonce-used-only-once-123"
+        raw_body = json.dumps(
+            {"externalUserId": "external-1001", "verifiedPhone": user.phone},
+            separators=(",", ":"),
+        ).encode()
+        payload = SsoTicketRequest.model_validate_json(raw_body)
+        signature = _signature(secret, timestamp, nonce, raw_body)
+        SsoService.issue_ticket(
+            db,
+            app_id=client.app_id,
+            timestamp=timestamp,
+            nonce=nonce,
+            signature=signature,
+            raw_body=raw_body,
+            payload=payload,
+            ip="127.0.0.1",
+        )
+
+        with pytest.raises(HTTPException) as replayed:
+            SsoService.issue_ticket(
+                db,
+                app_id=client.app_id,
+                timestamp=timestamp,
+                nonce=nonce,
+                signature=signature,
+                raw_body=raw_body,
+                payload=payload,
+                ip="127.0.0.1",
+            )
+        assert replayed.value.status_code == 409
+
+        another_nonce = "another-unique-nonce-456"
+        invalid_body = json.dumps(
+            {
+                "externalUserId": "external-1001",
+                "verifiedPhone": user.phone,
+                "returnUrl": "https://evil.example.com",
+            },
+            separators=(",", ":"),
+        ).encode()
+        with pytest.raises(HTTPException) as invalid_return:
+            SsoService.issue_ticket(
+                db,
+                app_id=client.app_id,
+                timestamp=timestamp,
+                nonce=another_nonce,
+                signature=_signature(secret, timestamp, another_nonce, invalid_body),
+                raw_body=invalid_body,
+                payload=SsoTicketRequest.model_validate_json(invalid_body),
+                ip="127.0.0.1",
+            )
+        assert invalid_return.value.status_code == 400
+
+
+def test_sso_first_login_requires_verified_existing_phone(monkeypatch: pytest.MonkeyPatch):
+    redis = FakeRedis()
+    monkeypatch.setattr("app.services.sso_service.get_sync_redis_client", lambda: redis)
+    with _db() as db:
+        _user, client, secret = _seed(db)
+        raw_body = b'{"externalUserId":"external-without-phone"}'
+        payload = SsoTicketRequest.model_validate_json(raw_body)
+        timestamp = str(int(time.time()))
+        nonce = "missing-phone-nonce-123"
+        with pytest.raises(HTTPException) as missing_phone:
+            SsoService.issue_ticket(
+                db,
+                app_id=client.app_id,
+                timestamp=timestamp,
+                nonce=nonce,
+                signature=_signature(secret, timestamp, nonce, raw_body),
+                raw_body=raw_body,
+                payload=payload,
+                ip="127.0.0.1",
+            )
+        assert missing_phone.value.status_code == 403
+        audit = db.scalar(select(SsoLoginAudit).order_by(SsoLoginAudit.id.desc()))
+        assert audit is not None
+        assert audit.status == "FAILED"
diff --git a/ai_knowledge_base_v2/apps/user-client/index.html b/ai_knowledge_base_v2/apps/user-client/index.html
index 1d5cc21..2eabc37 100644
--- a/ai_knowledge_base_v2/apps/user-client/index.html
+++ b/ai_knowledge_base_v2/apps/user-client/index.html
@@ -1,6 +1,7 @@
 <!doctype html>
 <html lang="zh-CN">
   <head>
+    <meta name="referrer" content="no-referrer" />
     <meta charset="UTF-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover" />
     <title>大本营答疑助手</title>
diff --git a/ai_knowledge_base_v2/apps/user-client/src/App.vue b/ai_knowledge_base_v2/apps/user-client/src/App.vue
index e0357ef..eada973 100644
--- a/ai_knowledge_base_v2/apps/user-client/src/App.vue
+++ b/ai_knowledge_base_v2/apps/user-client/src/App.vue
@@ -9,7 +9,7 @@ import MessageList, { type DisplayMessage } from "./components/MessageList.vue";
 import PersonalCenterDialog from "./components/PersonalCenterDialog.vue";
 import SessionDrawer from "./components/SessionDrawer.vue";
 import SessionQuota from "./components/SessionQuota.vue";
-import { ApiError, api, clearToken, getToken, streamChat } from "./services/api";
+import { ApiError, api, clearToken, getToken, saveToken, streamChat } from "./services/api";
 import type { ChatMessage as ApiMessage, ChatSession, PeriodicReport, PracticeReviewResult, ShareDraft, TeacherHelpCard, UserProfile } from "./types/api";
 
 const user = ref<UserProfile | null>(null);
@@ -48,7 +48,32 @@ const activeAbortController = ref<AbortController | null>(null);
 let toastTimer: number | null = null;
 let settlementPollVersion = 0;
 
-onMounted(async () => {
+onMounted(bootstrap);
+
+async function bootstrap() {
+  const search = new URLSearchParams(window.location.search);
+  const ssoCode = search.get("sso_code")?.trim() || "";
+  if (ssoCode) {
+    search.delete("sso_code");
+    const query = search.toString();
+    window.history.replaceState({}, "", `${window.location.pathname}${query ? `?${query}` : ""}${window.location.hash}`);
+    statusText.value = "正在完成免登录";
+    try {
+      const result = await api.exchangeSso(ssoCode);
+      saveToken(result.token);
+      if (result.returnUrl) window.sessionStorage.setItem("ai-kb-sso-return-url", result.returnUrl);
+      user.value = result.user;
+      await loadSessions();
+      statusText.value = "已连接大本营答疑服务";
+    } catch (error) {
+      clearUserState();
+      showToast(error instanceof Error ? `免登录失败：${error.message}` : "免登录失败，请重新进入或使用手机号登录");
+    } finally {
+      booting.value = false;
+    }
+    return;
+  }
+
   if (!getToken()) {
     booting.value = false;
     statusText.value = "请先登录";
@@ -63,7 +88,7 @@ onMounted(async () => {
   } finally {
     booting.value = false;
   }
-});
+}
 
 onBeforeUnmount(() => {
   settlementPollVersion += 1;
diff --git a/ai_knowledge_base_v2/apps/user-client/src/services/api.ts b/ai_knowledge_base_v2/apps/user-client/src/services/api.ts
index 1e75fbb..dfb91bf 100644
--- a/ai_knowledge_base_v2/apps/user-client/src/services/api.ts
+++ b/ai_knowledge_base_v2/apps/user-client/src/services/api.ts
@@ -85,6 +85,8 @@ export const api = {
     }),
   login: (phone: string, code: string) =>
     request<LoginResult>("/auth/login", { method: "POST", body: JSON.stringify({ phone, code }) }),
+  exchangeSso: (code: string) =>
+    request<LoginResult>("/auth/sso/exchange", { method: "POST", body: JSON.stringify({ code }) }),
   logout: () => request<null>("/auth/logout", { method: "POST", body: JSON.stringify({}) }),
   profile: () => request<UserProfile>("/user/profile"),
   createSession: () => request<{ sessionId: number }>("/chat/session", { method: "POST", body: JSON.stringify({}) }),
diff --git a/ai_knowledge_base_v2/apps/user-client/src/types/api.ts b/ai_knowledge_base_v2/apps/user-client/src/types/api.ts
index 42f158e..d4bfdf1 100644
--- a/ai_knowledge_base_v2/apps/user-client/src/types/api.ts
+++ b/ai_knowledge_base_v2/apps/user-client/src/types/api.ts
@@ -119,6 +119,7 @@ export interface LoginResult {
   token: string;
   expiredAt: string;
   user: UserProfile;
+  returnUrl?: string | null;
 }
 
 export interface CaptchaResult {
diff --git a/ai_knowledge_base_v2/docs/应用免登录接入说明.md b/ai_knowledge_base_v2/docs/应用免登录接入说明.md
new file mode 100644
index 0000000..6a39305
--- /dev/null
+++ b/ai_knowledge_base_v2/docs/应用免登录接入说明.md
@@ -0,0 +1,124 @@
+# 千问千答应用免登录接入说明
+
+## 1. 适用场景
+
+学员已经在其他可信应用完成登录，从该应用进入千问千答时，不再重复输入手机号和验证码。
+
+接入应用只能在自己的服务端申请一次性授权码。应用密钥不得写入网页、App 安装包、小程序或公开仓库。
+
+## 2. 准备工作
+
+管理员在千问千答后台的“应用接入”页面完成：
+
+1. 填写千问千答用户端公网地址；
+2. 新增接入应用；
+3. 保存系统只展示一次的应用密钥；
+4. 如需学员从千问千答返回来源应用，配置完整的回跳地址白名单。
+
+首次免登录时，接入应用必须提供学员在本应用内的稳定用户 ID 和已经由本应用验证过的手机号。手机号仅用于首次匹配千问千答学员，后续以账号绑定为准。
+
+## 3. 申请一次性授权码
+
+接口：
+
+```text
+POST /api/integration/sso/ticket
+```
+
+请求体示例：
+
+```json
+{"externalUserId":"student-10086","verifiedPhone":"13800138000","displayName":"张同学","returnUrl":"https://student.example.com/home"}
+```
+
+请求头：
+
+```text
+X-App-Id: 后台生成的应用ID
+X-Timestamp: 当前 Unix 秒级时间戳
+X-Nonce: 每次请求生成的唯一随机字符串，长度至少16位
+X-Signature: HMAC-SHA256 十六进制签名
+```
+
+签名原文：
+
+```text
+时间戳 + "\n" + 随机字符串 + "\n" + SHA256(原始请求体字节)
+```
+
+使用应用密钥对签名原文执行 HMAC-SHA256，输出小写十六进制字符串。必须对实际发送的原始 JSON 字节计算摘要，不要对解析后重新排序的对象签名。
+
+Python 示例：
+
+```python
+import hashlib
+import hmac
+import json
+import secrets
+import time
+
+body = json.dumps(
+    {
+        "externalUserId": "student-10086",
+        "verifiedPhone": "13800138000",
+        "displayName": "张同学",
+        "returnUrl": "https://student.example.com/home",
+    },
+    ensure_ascii=False,
+    separators=(",", ":"),
+).encode("utf-8")
+timestamp = str(int(time.time()))
+nonce = secrets.token_urlsafe(24)
+canonical = f"{timestamp}\n{nonce}\n{hashlib.sha256(body).hexdigest()}".encode()
+signature = hmac.new(APP_SECRET.encode(), canonical, hashlib.sha256).hexdigest()
+```
+
+成功响应：
+
+```json
+{
+  "code": 0,
+  "message": "success",
+  "data": {
+    "code": "一次性授权码",
+    "expiresInSeconds": 60,
+    "entryUrl": "https://qa.example.com/?sso_code=一次性授权码"
+  }
+}
+```
+
+接入应用收到响应后，让浏览器、App WebView 或小程序 WebView 打开 `entryUrl`。授权码只能使用一次，60 秒后自动失效。
+
+## 4. 用户匹配规则
+
+- 已经绑定：按“应用 ID + 外部用户 ID”直接找到千问千答学员；
+- 首次进入：使用已验证手机号匹配现有学员并建立绑定；
+- 手机号不在学员名单：拒绝进入，不自动创建无权益账号；
+- 学员已禁用、尚未生效或权益已过期：拒绝进入；
+- 同一应用中的一个千问千答学员只能绑定一个外部用户 ID。
+
+绑定错误时，管理员可以在“应用接入 → 账号绑定”中解除绑定，学员下次进入时重新核对手机号。
+
+## 5. 安全规则
+
+- 所有生产接口必须使用 HTTPS；
+- 应用密钥只保存在接入应用服务端；
+- 请求时间戳允许误差不超过 5 分钟；
+- `X-Nonce` 在 5 分钟内不得重复；
+- `returnUrl` 必须与后台白名单完全匹配；
+- Redis 不可用时停止签发和兑换授权码，不降级为长期 Token；
+- 更新应用密钥后，旧密钥立即失效；
+- 停用接入应用后，该应用不能继续申请或兑换登录态；
+- 登录成功和失败都会写入登录审计。
+
+## 6. 验收清单
+
+- 已登录来源应用的学员点击后直接进入千问千答；
+- 首次进入能按已验证手机号正确绑定；
+- 后续进入不再依赖手机号；
+- 同一个授权码第二次兑换失败；
+- 错误签名、过期时间戳、重复随机数均被拒绝；
+- 非白名单回跳地址被拒绝；
+- 禁用或过期学员不能进入；
+- 停用应用和更新密钥立即生效；
+- 手机号验证码登录仍可正常使用。