diff --git a/be/src/vec/functions/function_date_or_datetime_computation.cpp b/be/src/vec/functions/function_date_or_datetime_computation.cpp
index 8034d34c195e05..9506835c5d31d4 100644
--- a/be/src/vec/functions/function_date_or_datetime_computation.cpp
+++ b/be/src/vec/functions/function_date_or_datetime_computation.cpp
@@ -89,7 +89,7 @@ using FunctionLocalTimestamp =
         FunctionCurrentDateOrDateTime<CurrentDateTimeImpl<LocalTimestampFunctionName, false>>;
 
 using FunctionNowWithPrecision =
-        FunctionCurrentDateOrDateTime<CurrentDateTimeImpl<NowFunctionName, true>, false>;
+        FunctionCurrentDateOrDateTime<CurrentDateTimeImpl<NowFunctionName, true>>;
 using FunctionCurrentTimestampWithPrecision =
         FunctionCurrentDateOrDateTime<CurrentDateTimeImpl<CurrentTimestampFunctionName, true>>;
 using FunctionLocalTimeWithPrecision =
diff --git a/be/src/vec/functions/function_date_or_datetime_computation.h b/be/src/vec/functions/function_date_or_datetime_computation.h
index f91fe643b307b4..3ba1808c9cd6ac 100644
--- a/be/src/vec/functions/function_date_or_datetime_computation.h
+++ b/be/src/vec/functions/function_date_or_datetime_computation.h
@@ -832,7 +832,7 @@ class FunctionDateOrDateTimeComputation : public IFunction {
     }
 };
 
-template <typename FunctionImpl, bool DefaultNullable = true>
+template <typename FunctionImpl>
 class FunctionCurrentDateOrDateTime : public IFunction {
 public:
     static constexpr bool has_variadic_argument =
@@ -845,8 +845,6 @@ class FunctionCurrentDateOrDateTime : public IFunction {
 
     size_t get_number_of_arguments() const override { return 0; }
 
-    bool use_default_implementation_for_nulls() const override { return DefaultNullable; }
-
     DataTypePtr get_return_type_impl(const ColumnsWithTypeAndName& arguments) const override {
         return std::make_shared<typename FunctionImpl::ReturnType>();
     }
diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/Now.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/Now.java
index 19feb7684cb571..90b1f77a375494 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/Now.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/functions/scalar/Now.java
@@ -19,7 +19,6 @@
 
 import org.apache.doris.catalog.FunctionSignature;
 import org.apache.doris.nereids.trees.expressions.Expression;
-import org.apache.doris.nereids.trees.expressions.functions.AlwaysNotNullable;
 import org.apache.doris.nereids.trees.expressions.functions.DateTimeWithPrecision;
 import org.apache.doris.nereids.trees.expressions.functions.ExplicitlyCastableSignature;
 import org.apache.doris.nereids.trees.expressions.functions.Nondeterministic;
@@ -36,8 +35,7 @@
 /**
  * ScalarFunction 'now'. This class is generated by GenerateFunction.
  */
-public class Now extends DateTimeWithPrecision
-        implements ExplicitlyCastableSignature, Nondeterministic, AlwaysNotNullable {
+public class Now extends DateTimeWithPrecision implements ExplicitlyCastableSignature, Nondeterministic {
 
     public static final List<FunctionSignature> SIGNATURES = ImmutableList.of(
             FunctionSignature.ret(DateTimeType.INSTANCE).args(),
@@ -72,6 +70,18 @@ public Now withChildren(List<Expression> children) {
         }
     }
 
+    /**
+     * Depend on child.
+     */
+    @Override
+    public boolean nullable() {
+        if (arity() == 0) {
+            return false;
+        }
+        Preconditions.checkArgument(children.size() == 1);
+        return child(0).nullable();
+    }
+
     @Override
     public List<FunctionSignature> getSignatures() {
         return SIGNATURES;
diff --git a/gensrc/script/doris_builtins_functions.py b/gensrc/script/doris_builtins_functions.py
index 31c1bef74dc1e7..a0141972a9352f 100644
--- a/gensrc/script/doris_builtins_functions.py
+++ b/gensrc/script/doris_builtins_functions.py
@@ -857,8 +857,8 @@
         [['from_unixtime'], 'VARCHAR', ['INT'], 'ALWAYS_NULLABLE'],
         [['from_unixtime'], 'VARCHAR', ['INT', 'VARCHAR'], 'ALWAYS_NULLABLE'],
         [['from_unixtime'], 'VARCHAR', ['INT', 'STRING'], 'ALWAYS_NULLABLE'],
-        [['now', 'current_timestamp', 'localtime', 'localtimestamp'], 'DATETIME', [], 'ALWAYS_NOT_NULLABLE'],
-        [['now', 'current_timestamp', 'localtime', 'localtimestamp'], 'DATETIMEV2', ['INT'], 'ALWAYS_NOT_NULLABLE'],
+        [['now', 'current_timestamp', 'localtime', 'localtimestamp'], 'DATETIME', [], 'DEPEND_ON_ARGUMENT'],
+        [['now', 'current_timestamp', 'localtime', 'localtimestamp'], 'DATETIMEV2', ['INT'], 'DEPEND_ON_ARGUMENT'],
         [['curtime', 'current_time'], 'TIME', [], 'ALWAYS_NOT_NULLABLE'],
         [['curdate', 'current_date'], 'DATE', [], 'ALWAYS_NOT_NULLABLE'],
         [['utc_timestamp'], 'DATETIME', [], 'ALWAYS_NOT_NULLABLE'],
diff --git a/regression-test/suites/query_p0/sql_functions/datetime_functions/test_date_function.groovy b/regression-test/suites/query_p0/sql_functions/datetime_functions/test_date_function.groovy
index 6debd4d0b823ac..f3d775408ecbd5 100644
--- a/regression-test/suites/query_p0/sql_functions/datetime_functions/test_date_function.groovy
+++ b/regression-test/suites/query_p0/sql_functions/datetime_functions/test_date_function.groovy
@@ -317,6 +317,8 @@ suite("test_date_function") {
     // NOW
     def now_result = sql """ select now() """
     assertTrue(now_result[0].size() == 1)
+    def now_null_result = sql """ select now(null) """
+    assertTrue(now_null_result[0].size() == 1)
 
     // SECOND
     qt_sql """ select second('2018-12-31 23:59:59') """