diff --git a/server/chat_flow_task_main.py b/server/chat_flow_task_main.py
index c5720a6..658a0e5 100644
--- a/server/chat_flow_task_main.py
+++ b/server/chat_flow_task_main.py
@@ -462,9 +462,61 @@ async def handle_task_with_sender(terminal: WebTerminal, workspace: UserWorkspac
         state["suppress_next"] = False
     
     # 添加到对话历史
+    user_work_started_at = datetime.now().isoformat()
+    user_message_index = -1
+    user_work_finalized = False
     history_len_before = len(getattr(web_terminal.context_manager, "conversation_history", []) or [])
     is_first_user_message = history_len_before == 0
-    web_terminal.context_manager.add_conversation("user", message, images=images, videos=videos)
+    web_terminal.context_manager.add_conversation(
+        "user",
+        message,
+        images=images,
+        videos=videos,
+        metadata={
+            "work_timer": {
+                "status": "working",
+                "started_at": user_work_started_at
+            }
+        }
+    )
+    try:
+        user_message_index = len(getattr(web_terminal.context_manager, "conversation_history", []) or []) - 1
+    except Exception:
+        user_message_index = -1
+
+    def finalize_user_work_timer():
+        nonlocal user_work_finalized
+        if user_work_finalized:
+            return
+        history = getattr(web_terminal.context_manager, "conversation_history", None) or []
+        if user_message_index < 0 or user_message_index >= len(history):
+            return
+        target_msg = history[user_message_index] or {}
+        if target_msg.get("role") != "user":
+            return
+        metadata = target_msg.get("metadata") or {}
+        timer = metadata.get("work_timer")
+        if not isinstance(timer, dict):
+            timer = {}
+        started_at = timer.get("started_at") or target_msg.get("timestamp") or user_work_started_at
+        start_ts = None
+        try:
+            start_ts = datetime.fromisoformat(str(started_at).replace("Z", "+00:00")).timestamp()
+        except Exception:
+            start_ts = None
+        now_ts = time.time()
+        duration_ms = int(max(0.0, (now_ts - start_ts) * 1000.0)) if start_ts is not None else 0
+        timer.update({
+            "status": "completed",
+            "started_at": started_at,
+            "finished_at": datetime.now().isoformat(),
+            "duration_ms": duration_ms
+        })
+        metadata["work_timer"] = timer
+        target_msg["metadata"] = metadata
+        history[user_message_index] = target_msg
+        web_terminal.context_manager.auto_save_conversation(force=True)
+        user_work_finalized = True
 
     # Skill 提示系统：检测关键词并在用户消息之后插入 system 消息
     try:
@@ -535,6 +587,7 @@ async def handle_task_with_sender(terminal: WebTerminal, workspace: UserWorkspac
                 'status_code': 400,
                 'error_type': 'context_overflow'
             })
+            finalize_user_work_timer()
             return
         usage_percent = (current_tokens / max_context_tokens) * 100
         warned = web_terminal.context_manager.conversation_metadata.get("context_warning_sent", False)
@@ -649,6 +702,7 @@ async def handle_task_with_sender(terminal: WebTerminal, workspace: UserWorkspac
                 'message': "配额已达到上限，暂时无法继续调用模型。",
                 'quota': quota_info
             })
+            finalize_user_work_timer()
             return
         
         tool_call_limit_label = MAX_TOTAL_TOOL_CALLS if MAX_TOTAL_TOOL_CALLS is not None else "∞"
@@ -687,6 +741,7 @@ async def handle_task_with_sender(terminal: WebTerminal, workspace: UserWorkspac
             accumulated_response=accumulated_response,
         )
         if stream_result.get("stopped"):
+            finalize_user_work_timer()
             return
 
         full_response = stream_result["full_response"]
@@ -859,6 +914,7 @@ async def handle_task_with_sender(terminal: WebTerminal, workspace: UserWorkspac
         )
         last_tool_call_time = tool_loop_result.get("last_tool_call_time", last_tool_call_time)
         if tool_loop_result.get("stopped"):
+            finalize_user_work_timer()
             return
         
         # 标记不再是第一次迭代
@@ -923,6 +979,8 @@ async def handle_task_with_sender(terminal: WebTerminal, workspace: UserWorkspac
             socketio.start_background_task(run_poll)
 
     # 发送完成事件（如果有子智能体在运行，前端会保持等待状态）
+    if not has_running_sub_agents:
+        finalize_user_work_timer()
     sender('task_complete', {
         'total_iterations': total_iterations,
         'total_tool_calls': total_tool_calls,
diff --git a/static/src/app/methods/history.ts b/static/src/app/methods/history.ts
index 2588e8b..eb82300 100644
--- a/static/src/app/methods/history.ts
+++ b/static/src/app/methods/history.ts
@@ -165,7 +165,8 @@ export const historyMethods = {
                     role: 'user',
                     content: message.content || '',
                     images,
-                    videos
+                    videos,
+                    metadata: message.metadata || {}
                 });
                 debugLog('添加用户消息:', message.content?.substring(0, 50) + '...');
 
diff --git a/static/src/app/methods/taskPolling.ts b/static/src/app/methods/taskPolling.ts
index dbd505e..de7f713 100644
--- a/static/src/app/methods/taskPolling.ts
+++ b/static/src/app/methods/taskPolling.ts
@@ -653,6 +653,34 @@ export const taskPollingMethods = {
         this.conditionalScrollToBottom();
     },
 
+    markLatestUserWorkCompleted() {
+        if (!Array.isArray(this.messages) || this.messages.length === 0) {
+            return;
+        }
+        for (let i = this.messages.length - 1; i >= 0; i -= 1) {
+            const msg = this.messages[i];
+            if (!msg || msg.role !== 'user') {
+                continue;
+            }
+            msg.metadata = msg.metadata || {};
+            msg.metadata.work_timer = msg.metadata.work_timer || {};
+            const timer = msg.metadata.work_timer;
+            if (timer.status === 'completed' && typeof timer.duration_ms === 'number') {
+                return;
+            }
+            const nowIso = new Date().toISOString();
+            const startedAt = timer.started_at || msg.timestamp || nowIso;
+            const startMs = Date.parse(startedAt);
+            const endMs = Date.now();
+            const durationMs = Number.isFinite(startMs) ? Math.max(0, endMs - startMs) : 0;
+            timer.status = 'completed';
+            timer.started_at = startedAt;
+            timer.finished_at = nowIso;
+            timer.duration_ms = durationMs;
+            return;
+        }
+    },
+
     handleTaskComplete(data: any) {
         const hasRunningSubAgents = !!data?.has_running_sub_agents;
         if (hasRunningSubAgents) {
@@ -664,6 +692,9 @@ export const taskPollingMethods = {
         // 同步处理状态更新
         this.streamingMessage = false;
         this.stopRequested = false;
+        if (!hasRunningSubAgents) {
+            this.markLatestUserWorkCompleted();
+        }
 
         if (hasRunningSubAgents) {
             this.taskInProgress = true;
@@ -688,6 +719,7 @@ export const taskPollingMethods = {
     handleTaskStopped(data: any, eventIdx: number) {
         debugLog('[TaskPolling] 任务已停止, idx:', eventIdx, data);
 
+        this.markLatestUserWorkCompleted();
         this.streamingMessage = false;
         this.taskInProgress = false;
         this.stopRequested = false;
@@ -790,6 +822,7 @@ export const taskPollingMethods = {
         });
 
         // 清理状态
+        this.markLatestUserWorkCompleted();
         this.streamingMessage = false;
         this.taskInProgress = false;
         this.stopRequested = false;
diff --git a/static/src/components/chat/ChatArea.vue b/static/src/components/chat/ChatArea.vue
index 35fe352..ae5cab6 100644
--- a/static/src/components/chat/ChatArea.vue
+++ b/static/src/components/chat/ChatArea.vue
@@ -27,6 +27,7 @@
           <div v-if="index > 0 && filteredMessages[index - 1].role === 'user' && (msg.actions?.length > 0 || msg.awaitingFirstContent)" class="message-header icon-label">
             <span class="icon icon-sm" :style="iconStyleSafe('bot')" aria-hidden="true"></span>
             <span>{{ aiAssistantName }}</span>
+            <span v-if="assistantWorkLabel(index)" class="assistant-work-status">{{ assistantWorkLabel(index) }}</span>
           </div>
           <div
             v-if="msg.awaitingFirstContent"
@@ -379,7 +380,7 @@
 </template>
 
 <script setup lang="ts">
-import { computed, ref } from 'vue';
+import { computed, onBeforeUnmount, onMounted, ref } from 'vue';
 import ToolAction from '@/components/chat/actions/ToolAction.vue';
 import StackedBlocks from './StackedBlocks.vue';
 import MinimalBlocks from './MinimalBlocks.vue';
@@ -426,6 +427,8 @@ const filteredMessages = computed(() =>
   (props.messages || []).filter(m => !(m && m.metadata && m.metadata.system_injected_image) && m.role !== 'system')
 );
 const latestMessageIndex = computed(() => filteredMessages.value.length - 1);
+const nowMs = ref(Date.now());
+let timerHandle: number | null = null;
 
 const DEFAULT_GENERATING_TEXT = '生成中…';
 const rootEl = ref<HTMLElement | null>(null);
@@ -472,6 +475,56 @@ function getPreviewUrl(path: string): string {
   return `/api/gui/files/download?path=${encodeURIComponent(path)}`;
 }
 
+function formatDurationMs(durationMs: number): string {
+  const totalSeconds = Math.max(0, Math.floor((durationMs || 0) / 1000));
+  const hours = Math.floor(totalSeconds / 3600);
+  const minutes = Math.floor((totalSeconds % 3600) / 60);
+  const seconds = totalSeconds % 60;
+  if (hours > 0) {
+    return `${String(hours).padStart(2, '0')}:${String(minutes).padStart(2, '0')}:${String(seconds).padStart(2, '0')}`;
+  }
+  return `${String(minutes).padStart(2, '0')}:${String(seconds).padStart(2, '0')}`;
+}
+
+function assistantWorkLabel(index: number): string {
+  if (index <= 0) {
+    return '';
+  }
+  const prev = filteredMessages.value[index - 1];
+  if (!prev || prev.role !== 'user') {
+    return '';
+  }
+  const timer = prev?.metadata?.work_timer;
+  if (!timer || !timer.started_at) {
+    return '';
+  }
+  const startMs = Date.parse(timer.started_at);
+  if (!Number.isFinite(startMs)) {
+    return '';
+  }
+  const status = timer.status || 'working';
+  if (status === 'working') {
+    return `工作中 ${formatDurationMs(nowMs.value - startMs)}`;
+  }
+  const durationMs = typeof timer.duration_ms === 'number'
+    ? timer.duration_ms
+    : Math.max(0, (Number.isFinite(Date.parse(timer.finished_at || '')) ? Date.parse(timer.finished_at) : nowMs.value) - startMs);
+  return `工作完成 ${formatDurationMs(durationMs)}`;
+}
+
+onMounted(() => {
+  timerHandle = window.setInterval(() => {
+    nowMs.value = Date.now();
+  }, 1000);
+});
+
+onBeforeUnmount(() => {
+  if (timerHandle !== null) {
+    clearInterval(timerHandle);
+    timerHandle = null;
+  }
+});
+
 const isStackable = (action: any) => action && (action.type === 'thinking' || action.type === 'tool');
 const isEmptyTextAction = (action: any) => {
   if (!action || action.type !== 'text') {
diff --git a/static/src/stores/chat.ts b/static/src/stores/chat.ts
index 5db0aa1..65254a5 100644
--- a/static/src/stores/chat.ts
+++ b/static/src/stores/chat.ts
@@ -165,11 +165,18 @@ export const useChatStore = defineStore('chat', {
       return message;
     },
     addUserMessage(content: string, images: string[] = [], videos: string[] = []) {
+      const startedAt = new Date().toISOString();
       this.messages.push({
         role: 'user',
         content,
         images,
-        videos
+        videos,
+        metadata: {
+          work_timer: {
+            status: 'working',
+            started_at: startedAt
+          }
+        }
       });
       this.currentMessageIndex = -1;
     },
diff --git a/static/src/styles/components/chat/_chat-area.scss b/static/src/styles/components/chat/_chat-area.scss
index 9bd709a..fc82856 100644
--- a/static/src/styles/components/chat/_chat-area.scss
+++ b/static/src/styles/components/chat/_chat-area.scss
@@ -114,7 +114,7 @@
 .scroll-lock-toggle {
     position: fixed;
     right: 8px;
-    bottom: 140px;
+    bottom: 100px;
     z-index: 25;
     display: flex;
     align-items: center;
@@ -378,6 +378,13 @@
     letter-spacing: 0.02em;
 }
 
+.assistant-work-status {
+    margin-left: 8px;
+    font-size: 12px;
+    font-weight: 500;
+    color: var(--claude-text-secondary);
+}
+
 .user-message .message-text,
 .assistant-message .message-text {
     padding: 16px 20px;