diff --git a/fe/fe-core/src/main/java/org/apache/doris/analysis/IsNullPredicate.java b/fe/fe-core/src/main/java/org/apache/doris/analysis/IsNullPredicate.java
index 3263551c8a..a837079206 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/analysis/IsNullPredicate.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/analysis/IsNullPredicate.java
@@ -21,6 +21,7 @@
 package org.apache.doris.analysis;
 
 import org.apache.doris.catalog.Function;
+import org.apache.doris.catalog.Function.NullableMode;
 import org.apache.doris.catalog.FunctionSet;
 import org.apache.doris.catalog.ScalarFunction;
 import org.apache.doris.catalog.Type;
@@ -54,12 +55,12 @@ public class IsNullPredicate extends Predicate {
                         + "EEENS2_10BooleanValEPNS2_15FunctionContextERKT_";
             }
 
-            functionSet.addBuiltinBothScalaAndVectorized(ScalarFunction.createBuiltinOperator(
-                    IS_NULL, isNullSymbol, Lists.newArrayList(t), Type.BOOLEAN));
+            functionSet.addBuiltinBothScalaAndVectorized(ScalarFunction.createBuiltinOperator(IS_NULL, isNullSymbol,
+                    Lists.newArrayList(t), Type.BOOLEAN, NullableMode.ALWAYS_NOT_NULLABLE));
 
             String isNotNullSymbol = isNullSymbol.replace("7is_null", "11is_not_null");
-            functionSet.addBuiltinBothScalaAndVectorized(ScalarFunction.createBuiltinOperator(
-                    IS_NOT_NULL, isNotNullSymbol, Lists.newArrayList(t), Type.BOOLEAN));
+            functionSet.addBuiltinBothScalaAndVectorized(ScalarFunction.createBuiltinOperator(IS_NOT_NULL,
+                    isNotNullSymbol, Lists.newArrayList(t), Type.BOOLEAN, NullableMode.ALWAYS_NOT_NULLABLE));
         }
     }