diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/cluster/RemoteInstance.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/cluster/RemoteInstance.java
index a3b4e62d8..7b0d48f0f 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/cluster/RemoteInstance.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/cluster/RemoteInstance.java
@@ -37,7 +37,7 @@ public class RemoteInstance implements Comparable<RemoteInstance> {
     }
 
     @Override public int compareTo(RemoteInstance o) {
-        return toString().compareTo(toString());
+        return toString().compareTo(o.toString());
     }
 
     @Override public String toString() {