diff --git a/service/dao/servicesentinel.go b/service/dao/servicesentinel.go
index 9131b68..53c8d35 100644
--- a/service/dao/servicesentinel.go
+++ b/service/dao/servicesentinel.go
@@ -190,7 +190,7 @@ func (ss *ServiceSentinel) OnMonitorDelete(id uint64) {
 	defer ss.monitorsLock.Unlock()
 	delete(ss.monitors, id)
 	ss.monthlyStatusLock.Lock()
-	defer ss.monitorsLock.Unlock()
+	defer ss.monthlyStatusLock.Unlock()
 	delete(ss.monthlyStatus, id)
 }