diff --git a/inlong-sdk/transform-sdk/src/main/java/org/apache/inlong/sdk/transform/process/function/EltFunction.java b/inlong-sdk/transform-sdk/src/main/java/org/apache/inlong/sdk/transform/process/function/EltFunction.java
index e32f75d785..4eae49423c 100644
--- a/inlong-sdk/transform-sdk/src/main/java/org/apache/inlong/sdk/transform/process/function/EltFunction.java
+++ b/inlong-sdk/transform-sdk/src/main/java/org/apache/inlong/sdk/transform/process/function/EltFunction.java
@@ -28,6 +28,13 @@
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * EltFunction -> elt(index, expr[, exprs]*)
+ * description:
+ * - Returns the index-th expression.
+ * - index must be an integer between 1 and the number of expressions.
+ * - Returns NULL if index is NULL or out of range.
+ */
 @TransformFunction(names = {"elt"})
 public class EltFunction implements ValueParser {