diff --git a/ai_knowledge_base_v2/apps/backend/app/services/model_service.py b/ai_knowledge_base_v2/apps/backend/app/services/model_service.py
index 0530a58..d18e608 100644
--- a/ai_knowledge_base_v2/apps/backend/app/services/model_service.py
+++ b/ai_knowledge_base_v2/apps/backend/app/services/model_service.py
@@ -10,7 +10,7 @@ from sqlalchemy import select
 from sqlalchemy.orm import Session
 
 from app.core.config import get_settings
-from app.models.ai_config import ModelConfig
+from app.models.ai_config import ModelConfig, SystemConfig
 from app.services.external_errors import ExternalServiceError
 from app.services.rag_service import NO_HIT_ANSWER, RagResult
 
@@ -27,17 +27,19 @@ class ModelCompletion:
 class ModelClientService:
     @staticmethod
     def complete(db: Session, rag_result: RagResult) -> ModelCompletion:
+        mock_model_enabled = _system_config_bool(db, "mock_model_enabled", get_settings().mock_model_enabled)
         model = db.scalar(
             select(ModelConfig)
             .where(ModelConfig.enabled == 1)
             .order_by(ModelConfig.id.desc())
             .limit(1)
         )
-        settings = get_settings()
-        if settings.mock_model_enabled or model is None:
+        if mock_model_enabled:
             model_name = model.model_name if model is not None else "mock-model"
             answer = _mock_answer(rag_result)
         else:
+            if model is None:
+                raise ExternalServiceError("未启用可用模型，请先在模型管理中启用一个模型。", provider="model")
             model_name = model.model_name
             answer = _call_configured_model(model, rag_result)
 
@@ -92,6 +94,13 @@ def _mock_answer(rag_result: RagResult) -> str:
     )
 
 
+def _system_config_bool(db: Session, key: str, default: bool) -> bool:
+    config = db.scalar(select(SystemConfig).where(SystemConfig.config_key == key))
+    if config is None or not config.config_value.strip():
+        return default
+    return config.config_value.strip().lower() in {"1", "true", "yes", "on", "启用"}
+
+
 def _copy_model_with_overrides(model: ModelConfig, overrides: dict[str, Any]) -> ModelConfig:
     debug_model = ModelConfig(
         provider=model.provider,
diff --git a/ai_knowledge_base_v2/apps/user-client/src/components/ChatMessage.vue b/ai_knowledge_base_v2/apps/user-client/src/components/ChatMessage.vue
index ce3bb27..fa63177 100644
--- a/ai_knowledge_base_v2/apps/user-client/src/components/ChatMessage.vue
+++ b/ai_knowledge_base_v2/apps/user-client/src/components/ChatMessage.vue
@@ -14,9 +14,32 @@ const markdown = new MarkdownIt({
   linkify: true,
 });
 
+const assistantParts = computed(() => {
+  if (props.role === "user") {
+    return { reasoning: "", answer: props.content };
+  }
+  const matched = props.content.match(/<think>([\s\S]*?)<\/think>/i);
+  if (matched) {
+    return {
+      reasoning: matched[1].trim(),
+      answer: props.content.replace(matched[0], "").trim(),
+    };
+  }
+  const opening = props.content.match(/<think>([\s\S]*)$/i);
+  if (opening) {
+    return {
+      reasoning: opening[1].trim(),
+      answer: props.content.slice(0, opening.index).trim(),
+    };
+  }
+  return { reasoning: "", answer: props.content };
+});
+
+const renderedReasoning = computed(() => markdown.render(assistantParts.value.reasoning || ""));
+
 const renderedContent = computed(() => {
   if (props.role === "user") return props.content;
-  return markdown.render(props.content || "");
+  return markdown.render(assistantParts.value.answer || "");
 });
 </script>
 
@@ -24,7 +47,13 @@ const renderedContent = computed(() => {
   <article class="message" :class="role">
     <div class="avatar">{{ role === "assistant" ? "AI" : "我" }}</div>
     <div class="bubble">
-      <div v-if="role === 'assistant'" class="content markdown-content" v-html="renderedContent"></div>
+      <template v-if="role === 'assistant'">
+        <details v-if="assistantParts.reasoning" class="reasoning-panel" :open="streaming">
+          <summary>{{ streaming ? "思考中" : "思考过程" }}</summary>
+          <div class="markdown-content reasoning-content" v-html="renderedReasoning"></div>
+        </details>
+        <div class="content markdown-content" v-html="renderedContent"></div>
+      </template>
       <div v-else class="content">{{ renderedContent }}</div>
       <span v-if="streaming" class="typing">正在生成</span>
     </div>
diff --git a/ai_knowledge_base_v2/apps/user-client/src/styles.css b/ai_knowledge_base_v2/apps/user-client/src/styles.css
index be52015..5d1e907 100644
--- a/ai_knowledge_base_v2/apps/user-client/src/styles.css
+++ b/ai_knowledge_base_v2/apps/user-client/src/styles.css
@@ -291,6 +291,33 @@ button:disabled {
   white-space: normal;
 }
 
+.reasoning-panel {
+  margin-bottom: 10px;
+  border: 1px solid #dbe7e3;
+  border-radius: 12px;
+  background: #f2f7f5;
+  color: #496259;
+}
+
+.reasoning-panel summary {
+  min-height: 36px;
+  display: flex;
+  align-items: center;
+  padding: 0 10px;
+  color: #315d52;
+  font-size: 13px;
+  font-weight: 700;
+  cursor: pointer;
+}
+
+.reasoning-content {
+  max-height: 220px;
+  overflow-y: auto;
+  padding: 0 10px 10px;
+  color: #5d7169;
+  font-size: 13px;
+}
+
 .markdown-content > :first-child {
   margin-top: 0;
 }