diff --git a/sentinel-cluster/sentinel-cluster-server-default/src/main/java/com/alibaba/csp/sentinel/cluster/server/connection/ConnectionGroup.java b/sentinel-cluster/sentinel-cluster-server-default/src/main/java/com/alibaba/csp/sentinel/cluster/server/connection/ConnectionGroup.java
index 9a3d53cd28..4fb3376084 100644
--- a/sentinel-cluster/sentinel-cluster-server-default/src/main/java/com/alibaba/csp/sentinel/cluster/server/connection/ConnectionGroup.java
+++ b/sentinel-cluster/sentinel-cluster-server-default/src/main/java/com/alibaba/csp/sentinel/cluster/server/connection/ConnectionGroup.java
@@ -19,6 +19,7 @@
 import java.util.HashSet;
 import java.util.Set;
 import java.util.concurrent.ConcurrentSkipListSet;
+import java.util.concurrent.CopyOnWriteArraySet;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import com.alibaba.csp.sentinel.cluster.server.ServerConstants;
@@ -34,7 +35,7 @@ public class ConnectionGroup {
 
     private final String namespace;
 
-    private final Set<ConnectionDescriptor> connectionSet = Collections.synchronizedSet(new HashSet<ConnectionDescriptor>());
+    private final Set<ConnectionDescriptor> connectionSet = new CopyOnWriteArraySet<>();
     private final AtomicInteger connectedCount = new AtomicInteger();
 
     public ConnectionGroup(String namespace) {