diff --git a/inlong-sdk/transform-sdk/src/main/java/org/apache/inlong/sdk/transform/process/function/ContainsFunction.java b/inlong-sdk/transform-sdk/src/main/java/org/apache/inlong/sdk/transform/process/function/ContainsFunction.java
index e316965dde4..e2905eea07e 100644
--- a/inlong-sdk/transform-sdk/src/main/java/org/apache/inlong/sdk/transform/process/function/ContainsFunction.java
+++ b/inlong-sdk/transform-sdk/src/main/java/org/apache/inlong/sdk/transform/process/function/ContainsFunction.java
@@ -51,6 +51,6 @@ public Object parse(SourceData sourceData, int rowIndex, Context context) {
         Object rightStrObj = rightStrParser.parse(sourceData, rowIndex, context);
         String leftStr = OperatorTools.parseString(leftStrObj);
         String rightStr = OperatorTools.parseString(rightStrObj);
-        return leftStr.contains(rightStr);
+        return (leftStr == null || rightStr == null) ? null : leftStr.contains(rightStr);
     }
 }