diff --git a/CHANGES.md b/CHANGES.md
index ee1ed2376526600e46dc3d7e9066f317c84ba0a4..dbe24b893bef986a97a313f2456acce6987ec3bd 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -44,6 +44,7 @@ Release Notes.
 * Add a new API to test log analysis language.
 * Harden the security of Groovy-based DSL, MAL and LAL.
 * Fix distinct in Service/Instance/Endpoint query is not working.
+* Fix NPE when OAP nodes synchronize events with each other in cluster mode.
 
 #### UI
 
diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/source/Event.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/source/Event.java
index f985d0834e150bad671d60ab9e16a596b2119e9b..52f5b9f1c1eb7c0ec78fdec8fef9c0dc8b1c5504 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/source/Event.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/source/Event.java
@@ -18,6 +18,7 @@
 
 package org.apache.skywalking.oap.server.core.source;
 
+import com.google.common.base.Strings;
 import java.util.HashMap;
 import java.util.Map;
 import lombok.EqualsAndHashCode;
@@ -186,7 +187,7 @@ public class Event extends Metrics implements ISource, WithMetadata, LongValueHo
         builder.addDataStrings(getName());
         builder.addDataStrings(getType());
         builder.addDataStrings(getMessage());
-        builder.addDataStrings(getParameters());
+        builder.addDataStrings(Strings.nullToEmpty(getParameters()));
 
         builder.addDataLongs(getStartTime());
         builder.addDataLongs(getEndTime());