diff --git a/server/tasks.py b/server/tasks.py
index 4763750..8160c84 100644
--- a/server/tasks.py
+++ b/server/tasks.py
@@ -75,6 +75,22 @@ class TaskManager:
         self._tasks: Dict[str, TaskRecord] = {}
         self._lock = threading.Lock()
 
+    def cleanup_old_tasks(self, max_age_seconds: int = 3600) -> int:
+        """清理超过指定时间的已完成任务"""
+        now = time.time()
+        with self._lock:
+            to_remove = []
+            for task_id, rec in self._tasks.items():
+                if rec.status in {"succeeded", "failed", "canceled"}:
+                    age = now - rec.updated_at
+                    if age > max_age_seconds:
+                        to_remove.append(task_id)
+
+            for task_id in to_remove:
+                del self._tasks[task_id]
+
+            return len(to_remove)
+
     # ---- public APIs ----
     def create_chat_task(
         self,
@@ -274,6 +290,27 @@ task_manager = TaskManager()
 tasks_bp = Blueprint("tasks", __name__)
 
 
+def start_task_cleanup_scheduler():
+    """启动任务清理定时器"""
+    def cleanup_loop():
+        while True:
+            try:
+                count = task_manager.cleanup_old_tasks(3600)
+                if count > 0:
+                    debug_log(f"[Task] 清理了 {count} 个旧任务")
+            except Exception as e:
+                debug_log(f"[Task] 清理任务失败: {e}")
+            time.sleep(600)  # 每 10 分钟
+
+    thread = threading.Thread(target=cleanup_loop, daemon=True, name="TaskCleanup")
+    thread.start()
+    debug_log("[Task] 任务清理定时器已启动")
+
+
+# 启动清理定时器
+start_task_cleanup_scheduler()
+
+
 @tasks_bp.route("/api/tasks", methods=["GET"])
 @api_login_required
 def list_tasks_api():
diff --git a/static/src/app/methods/taskPolling.ts b/static/src/app/methods/taskPolling.ts
index 51040c3..df6b7ed 100644
--- a/static/src/app/methods/taskPolling.ts
+++ b/static/src/app/methods/taskPolling.ts
@@ -609,12 +609,33 @@ export const taskPollingMethods = {
     },
 
     handleTaskError(data: any) {
+        const errorMessage = data.message || '未知错误';
+        const errorType = data.error_type || 'unknown';
+
+        let title = '任务执行失败';
+        let message = errorMessage;
+
+        // 根据错误类型提供友好提示
+        if (errorType === 'api_error') {
+            title = 'API 调用失败';
+            message = `模型服务异常：${errorMessage}`;
+        } else if (errorType === 'timeout') {
+            title = '任务超时';
+            message = '任务执行时间过长，已自动停止';
+        } else if (errorType === 'quota_exceeded') {
+            title = '配额不足';
+            message = '您的使用配额已用尽';
+        }
+
         console.error('[TaskPolling] 任务错误:', data.message);
         this.uiPushToast({
-            title: '任务执行失败',
-            message: data.message || '未知错误',
-            type: 'error'
+            title,
+            message,
+            type: 'error',
+            duration: 8000
         });
+
+        // 清理状态
         this.streamingMessage = false;
         this.taskInProgress = false;
         this.stopRequested = false;
diff --git a/static/src/stores/task.ts b/static/src/stores/task.ts
index 350b34d..812eeac 100644
--- a/static/src/stores/task.ts
+++ b/static/src/stores/task.ts
@@ -10,6 +10,7 @@ export const useTaskStore = defineStore('task', {
         taskStatus: 'idle' as 'idle' | 'running' | 'succeeded' | 'failed' | 'canceled',
         isPolling: false,
         pollingError: null as string | null,
+        pollingErrorCount: 0, // 新增错误计数
         taskCreatedAt: null as number | null,
         taskUpdatedAt: null as number | null,
     }),
@@ -74,11 +75,12 @@ export const useTaskStore = defineStore('task', {
 
             try {
                 const response = await fetch(
-                    `/api/tasks/${this.currentTaskId}?from=${this.lastEventIndex}`
+                    `/api/tasks/${this.currentTaskId}?from=${this.lastEventIndex}`,
+                    { signal: AbortSignal.timeout(5000) } // 5秒超时
                 );
 
                 if (!response.ok) {
-                    throw new Error('轮询任务失败');
+                    throw new Error(`HTTP ${response.status}`);
                 }
 
                 const result = await response.json();
@@ -113,14 +115,27 @@ export const useTaskStore = defineStore('task', {
                     this.stopPolling();
                 }
 
+                // 重置错误计数
                 this.pollingError = null;
+                this.pollingErrorCount = 0;
             } catch (error) {
-                console.error('[Task] 轮询失败:', error);
+                this.pollingErrorCount++;
                 this.pollingError = error.message;
 
-                // 连续失败3次后停止轮询
-                if (this.pollingError) {
-                    // 可以在这里添加重试逻辑
+                console.error('[Task] 轮询失败:', error);
+
+                // 连续失败 5 次后停止
+                if (this.pollingErrorCount >= 5) {
+                    this.stopPolling();
+                    // 通知用户
+                    if ((window as any).__vueApp?.uiPushToast) {
+                        (window as any).__vueApp.uiPushToast({
+                            title: '轮询失败',
+                            message: '请刷新页面重试',
+                            type: 'error',
+                            duration: 10000
+                        });
+                    }
                 }
             }
         },