diff --git a/internal/config/config.go b/internal/config/config.go
index 9e45038..c471d36 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -20,6 +20,7 @@ type Config struct {
     MediaRepoPath      string            `json:"media_repo_path,omitempty"` // explicit import-only source; not used for runtime rendering
     AlarmRetentionDays int               `json:"alarm_retention_days"`     // auto-delete alarms older than N days, 0=keep forever
     CompanyName        string            `json:"company_name,omitempty"`
+    TimeSyncThresholdSec int             `json:"time_sync_threshold_sec"`
     DeviceAliases      map[string]string `json:"device_aliases,omitempty"`
     path               string
 }
diff --git a/internal/service/task.go b/internal/service/task.go
index 48ba0c9..cf90511 100644
--- a/internal/service/task.go
+++ b/internal/service/task.go
@@ -442,7 +442,11 @@ func (s *TaskService) executeOnDevice(task *models.Task, did string) {
                 if diff < 0 {
                     diff = -diff
                 }
-                if diff <= 5 {
+                threshold := int64(s.cfg.TimeSyncThresholdSec)
+                if threshold <= 0 {
+                    threshold = 5
+                }
+                if diff <= threshold {
                     s.updateDeviceStatus(task.ID, did, models.TaskSuccess, 1.0, "时间已同步")
                     s.appendAuditLog(task, did, models.TaskSuccess, "")
                     return
diff --git a/internal/web/ui.go b/internal/web/ui.go
index fb906f4..e09ad3e 100644
--- a/internal/web/ui.go
+++ b/internal/web/ui.go
@@ -117,6 +117,7 @@ type PageData struct {
     SystemAlarmRetention     int
     SystemConcurrency        int
     SystemCompanyName        string
+    TimeSyncThreshold        int
     AlarmFilterDevices       []string
     AlarmFilterRuleTypes     []string
     AlarmDeviceNames         map[string]string
@@ -4400,6 +4401,10 @@ func (u *UI) renderSystemPage(w http.ResponseWriter, r *http.Request, status int
     if u.cfg != nil {
         data.SystemAlarmRetention = u.cfg.AlarmRetentionDays
         data.SystemCompanyName = u.cfg.CompanyName
+        data.TimeSyncThreshold = u.cfg.TimeSyncThresholdSec
+        if data.TimeSyncThreshold <= 0 {
+            data.TimeSyncThreshold = 5
+        }
     }
     u.render(w, r, "system", data)
 }
@@ -4422,6 +4427,10 @@ func (u *UI) actionSystemConfig(w http.ResponseWriter, r *http.Request) {
         u.cfg.CompanyName = company
         changed = true
     }
+    if tval, err := strconv.Atoi(strings.TrimSpace(r.FormValue("time_sync_threshold_sec"))); err == nil && tval >= 1 && u.cfg != nil {
+        u.cfg.TimeSyncThresholdSec = tval
+        changed = true
+    }
     if changed && u.cfg != nil && strings.TrimSpace(u.configPath) != "" {
         if data, err := json.MarshalIndent(u.cfg, "", "  "); err == nil {
             os.WriteFile(u.configPath, data, 0o644)
@@ -5292,6 +5301,10 @@ func (u *UI) deviceOverviewPageData(r *http.Request, selectedIDs []string, errMs
 
     // Check time drift
     now := time.Now().UnixMilli()
+    threshold := int64(5) // default
+    if u.cfg != nil && u.cfg.TimeSyncThresholdSec > 0 {
+        threshold = int64(u.cfg.TimeSyncThresholdSec)
+    }
     for i := range rows {
         dev := rows[i].Device
         if dev == nil || !dev.Online || u.agent == nil {
@@ -5313,6 +5326,12 @@ func (u *UI) deviceOverviewPageData(r *http.Request, selectedIDs []string, errMs
         }
     }
 
+    // Common threshold for time drift display
+    if threshold <= 0 {
+        threshold = 5
+    }
+    // (threshold used in template comparison: gt .TimeDriftSec $threshold)
+
     data := PageData{
         Title:              "设备管理",
         Devices:            devices,
diff --git a/internal/web/ui/templates/devices.html b/internal/web/ui/templates/devices.html
index 01a497b..704ef07 100644
--- a/internal/web/ui/templates/devices.html
+++ b/internal/web/ui/templates/devices.html
@@ -47,7 +47,7 @@
         {{if $allOffline}}
         <button type="submit" id="cleanup-btn" name="action" value="cleanup_offline" class="danger" style="display:none" onclick="var n=document.querySelectorAll('input[name=device_id]:checked').length;return confirm('确认清理选中的 '+n+' 台离线设备及其全部关联数据？此操作不可恢复。')">清理选中离线设备</button>
         {{end}}
-        {{$drift := false}}{{range .DeviceRows}}{{if and (gt .TimeDriftSec 5) (hasString $.SelectedDeviceIDs .Device.DeviceID)}}{{$drift = true}}{{end}}{{end}}
+        {{$drift := false}}{{range .DeviceRows}}{{if and (gt .TimeDriftSec $.TimeSyncThreshold) (hasString $.SelectedDeviceIDs .Device.DeviceID)}}{{$drift = true}}{{end}}{{end}}
         {{if $drift}}
         <button type="submit" name="action" value="time_sync" class="secondary">⏱ 时间同步</button>
         {{end}}
@@ -97,7 +97,7 @@
                     <span class="pill bad">未知</span>
                   {{end}}
                   {{if .IntegrationStale}}<span class="pill warn">需重新下发</span>{{end}}
-                  {{if gt .TimeDriftSec 5}}<span class="pill bad">⏱ 偏差{{.TimeDriftSec}}秒</span>{{end}}
+                  {{if gt .TimeDriftSec $.TimeSyncThreshold}}<span class="pill bad">⏱ 偏差{{.TimeDriftSec}}秒</span>{{end}}
                 </div>
               </div>
             </td>
diff --git a/internal/web/ui/templates/system.html b/internal/web/ui/templates/system.html
index 2dc5258..0176f2a 100644
--- a/internal/web/ui/templates/system.html
+++ b/internal/web/ui/templates/system.html
@@ -23,6 +23,13 @@
   </div>
 </div>
 
+<div class="card">
+  <h2 class="title-with-icon">{{icon "heartbeat"}}<span>本机时间</span></h2>
+  <div class="info-list compact-list">
+    <div><span>当前时间</span><strong id="local-time">--</strong></div>
+  </div>
+</div>
+
 <div class="detail-grid">
   <div class="card">
     <h2 class="title-with-icon">{{icon "heartbeat"}}<span>服务状态</span></h2>
@@ -40,6 +47,7 @@
       <div class="field-grid">
         <label><span>告警保留天数</span><input type="number" name="alarm_retention_days" value="{{.SystemAlarmRetention}}" min="0" /><div class="form-hint">0=永久保留</div></label>
         <label><span>公司名称</span><input type="text" name="company_name" value="{{.SystemCompanyName}}" placeholder="将在页面底部显示" /></label>
+        <label><span>时间同步阈值(秒)</span><input type="number" name="time_sync_threshold_sec" value="{{.TimeSyncThreshold}}" min="1" /><div class="form-hint">偏差超此值显示角标，默认5秒</div></label>
       </div>
       <div class="actions" style="margin-top:12px">
         <button type="submit" class="secondary">保存配置</button>
@@ -58,7 +66,6 @@
     svcEl.style.color = "";
     apiEl.textContent = "检测中…";
     apiEl.style.color = "";
-
     fetch("/health")
       .then(function(r) { return r.text(); })
       .then(function(t) {
@@ -74,7 +81,6 @@
         svcEl.textContent = "无法连接";
         svcEl.style.color = "var(--danger-soft-text)";
       });
-
     fetch("/openapi.json")
       .then(function(r) {
         if (r.ok) {
@@ -90,9 +96,21 @@
         apiEl.style.color = "var(--danger-soft-text)";
       });
   }
-
   document.getElementById("btn-refresh").addEventListener("click", check);
   check();
+
+  function updateTime() {
+    var now = new Date();
+    var s = now.getFullYear() + '-' +
+      String(now.getMonth()+1).padStart(2,'0') + '-' +
+      String(now.getDate()).padStart(2,'0') + ' ' +
+      String(now.getHours()).padStart(2,'0') + ':' +
+      String(now.getMinutes()).padStart(2,'0') + ':' +
+      String(now.getSeconds()).padStart(2,'0');
+    document.getElementById('local-time').textContent = s;
+  }
+  updateTime();
+  setInterval(updateTime, 1000);
 })();
 </script>
 {{end}}