diff --git a/dolphinscheduler-api/src/main/java/org/apache/dolphinscheduler/api/service/MonitorService.java b/dolphinscheduler-api/src/main/java/org/apache/dolphinscheduler/api/service/MonitorService.java
index e9877216f1..118c5ce936 100644
--- a/dolphinscheduler-api/src/main/java/org/apache/dolphinscheduler/api/service/MonitorService.java
+++ b/dolphinscheduler-api/src/main/java/org/apache/dolphinscheduler/api/service/MonitorService.java
@@ -119,8 +119,9 @@ public class MonitorService extends BaseService{
 
   public List<Server> getServerListFromZK(boolean isMaster){
 
+    checkNotNull(zookeeperMonitor);
     ZKNodeType zkNodeType = isMaster ? ZKNodeType.MASTER : ZKNodeType.WORKER;
-    return checkNotNull(zookeeperMonitor).getServersList(zkNodeType);
+    return zookeeperMonitor.getServersList(zkNodeType);
   }
 
 }