diff --git a/handlers/handler-loadbalance/src/main/java/org/apache/servicecomb/loadbalance/filter/IsolationDiscoveryFilter.java b/handlers/handler-loadbalance/src/main/java/org/apache/servicecomb/loadbalance/filter/IsolationDiscoveryFilter.java
index b81d2e25ca4..c4b99d31434 100644
--- a/handlers/handler-loadbalance/src/main/java/org/apache/servicecomb/loadbalance/filter/IsolationDiscoveryFilter.java
+++ b/handlers/handler-loadbalance/src/main/java/org/apache/servicecomb/loadbalance/filter/IsolationDiscoveryFilter.java
@@ -106,7 +106,7 @@ public DiscoveryTreeNode discovery(DiscoveryContext context, DiscoveryTreeNode p
       }
     });
 
-    DiscoveryTreeNode child = new DiscoveryTreeNode();
+    DiscoveryTreeNode child = parent.children().computeIfAbsent("filterred", etn -> new DiscoveryTreeNode());
     if (ZoneAwareDiscoveryFilter.GROUP_Instances_All
         .equals(context.getContextParameter(ZoneAwareDiscoveryFilter.KEY_ZONE_AWARE_STEP)) && filteredServers.isEmpty()
         && emptyProtection.get()) {