diff --git a/app/services/alarm_event_service.py b/app/services/alarm_event_service.py
index f5674dc..0674ac1 100644
--- a/app/services/alarm_event_service.py
+++ b/app/services/alarm_event_service.py
@@ -415,8 +415,22 @@ class AlarmEventService:
                 alarm.handle_remark = remark
             if handler:
                 alarm.handler = handler
-            alarm.handled_at = beijing_now()
-            alarm.updated_at = beijing_now()
+
+            now = beijing_now()
+            alarm.handled_at = now
+            alarm.updated_at = now
+
+            # 如果没有 duration_ms 且有 event_time，计算告警时长
+            if alarm.duration_ms is None and alarm.event_time:
+                try:
+                    delta = now - alarm.event_time
+                    alarm.duration_ms = int(delta.total_seconds() * 1000)
+                except Exception:
+                    pass
+
+            # 如果没有 last_frame_time，设置为当前处理时间
+            if alarm.last_frame_time is None:
+                alarm.last_frame_time = now
 
             db.commit()
             db.refresh(alarm)
diff --git a/app/services/device_service.py b/app/services/device_service.py
index f70e7af..4a7f7b5 100644
--- a/app/services/device_service.py
+++ b/app/services/device_service.py
@@ -7,6 +7,7 @@ from typing import Dict, Any, List, Optional
 
 from app.models import EdgeDevice, DeviceStatus, get_session
 from app.utils.logger import logger
+from app.utils.timezone import beijing_now
 
 
 class DeviceService:
@@ -32,7 +33,7 @@ class DeviceService:
         """检查离线设备"""
         db = get_session()
         try:
-            threshold = datetime.now(timezone.utc) - timedelta(seconds=self.OFFLINE_TIMEOUT)
+            threshold = beijing_now() - timedelta(seconds=self.OFFLINE_TIMEOUT)
 
             # 查找需要标记为离线的设备
             devices = db.query(EdgeDevice).filter(
@@ -43,7 +44,7 @@ class DeviceService:
             offline_devices = []
             for device in devices:
                 device.status = DeviceStatus.OFFLINE
-                device.updated_at = datetime.now(timezone.utc)
+                device.updated_at = beijing_now()
                 offline_devices.append(device)
                 logger.info(f"设备离线: {device.device_id}")
 
diff --git a/app/services/notification_service.py b/app/services/notification_service.py
index c5e2ce3..f527fee 100644
--- a/app/services/notification_service.py
+++ b/app/services/notification_service.py
@@ -9,6 +9,7 @@ from typing import Dict, Any, List, Set
 from fastapi import WebSocket
 
 from app.utils.logger import logger
+from app.utils.timezone import beijing_now
 
 
 class ConnectionManager:
@@ -80,7 +81,7 @@ class NotificationService:
         message = {
             "event": "new_alert",
             "data": alert_data,
-            "timestamp": datetime.utcnow().isoformat(),
+            "timestamp": beijing_now().isoformat(),
         }
         await self._manager.broadcast(message)
         logger.debug(f"已广播新告警通知: {alert_data.get('alert_no', 'N/A')}")
@@ -90,7 +91,7 @@ class NotificationService:
         message = {
             "event": "alert_updated",
             "data": alert_data,
-            "timestamp": datetime.utcnow().isoformat(),
+            "timestamp": beijing_now().isoformat(),
         }
         await self._manager.broadcast(message)
 
@@ -99,7 +100,7 @@ class NotificationService:
         message = {
             "event": "device_status",
             "data": device_data,
-            "timestamp": datetime.utcnow().isoformat(),
+            "timestamp": beijing_now().isoformat(),
         }
         await self._manager.broadcast(message)
 
@@ -108,7 +109,7 @@ class NotificationService:
         message = {
             "event": f"work_order_{event_type}",
             "data": order_data,
-            "timestamp": datetime.utcnow().isoformat(),
+            "timestamp": beijing_now().isoformat(),
         }
         await self._manager.broadcast(message)
 
@@ -121,7 +122,7 @@ class NotificationService:
         message = {
             "event": event,
             "data": data,
-            "timestamp": datetime.utcnow().isoformat(),
+            "timestamp": beijing_now().isoformat(),
         }
 
         async def _broadcast():
diff --git a/app/services/notify_dispatch.py b/app/services/notify_dispatch.py
index 53d0c8a..5c7c36f 100644
--- a/app/services/notify_dispatch.py
+++ b/app/services/notify_dispatch.py
@@ -22,6 +22,7 @@ from app.config import settings
 from app.services.vlm_service import get_vlm_service
 from app.services.wechat_service import get_wechat_service
 from app.utils.logger import logger
+from app.utils.timezone import beijing_now
 
 
 async def process_alarm_notification(alarm_data: Dict):
@@ -151,10 +152,20 @@ def _mark_false_alarm(alarm_id: str):
     try:
         alarm = db.query(AlarmEvent).filter(AlarmEvent.alarm_id == alarm_id).first()
         if alarm:
+            now = beijing_now()
             alarm.alarm_status = "FALSE"
             alarm.handle_status = "DONE"
             alarm.handle_remark = "VLM复核判定误报"
-            alarm.handled_at = datetime.now()
+            alarm.handled_at = now
+            # 计算告警时长（VLM复核时间 - 事件时间）
+            if alarm.duration_ms is None and alarm.event_time:
+                try:
+                    delta = now - alarm.event_time
+                    alarm.duration_ms = int(delta.total_seconds() * 1000)
+                except Exception:
+                    pass
+            if alarm.last_frame_time is None:
+                alarm.last_frame_time = now
             db.commit()
             logger.info(f"告警已标记误报: {alarm_id}")
     except Exception as e: