diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/literal/DateTimeV2Literal.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/literal/DateTimeV2Literal.java
index 2417d92e89addf3..483483dd59d5219 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/literal/DateTimeV2Literal.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/literal/DateTimeV2Literal.java
@@ -251,8 +251,8 @@ public DateTimeV2Literal roundCeiling(int newScale) {
     }
 
     public DateTimeV2Literal roundFloor(int newScale) {
-        // use roundMicroSecond in constructor
-        return new DateTimeV2Literal(DateTimeV2Type.of(newScale), year, month, day, hour, minute, second, microSecond);
+        return new DateTimeV2Literal(DateTimeV2Type.of(newScale), year, month, day, hour, minute, second,
+                microSecond / (int) Math.pow(10, 6 - newScale) * (int) Math.pow(10, 6 - newScale));
     }
 
     public static Expression fromJavaDateType(LocalDateTime dateTime) {
diff --git a/fe/fe-core/src/test/java/org/apache/doris/nereids/trees/expressions/literal/DateTimeLiteralTest.java b/fe/fe-core/src/test/java/org/apache/doris/nereids/trees/expressions/literal/DateTimeLiteralTest.java
index 184cf5dbf6342f4..81d09a918af13b2 100644
--- a/fe/fe-core/src/test/java/org/apache/doris/nereids/trees/expressions/literal/DateTimeLiteralTest.java
+++ b/fe/fe-core/src/test/java/org/apache/doris/nereids/trees/expressions/literal/DateTimeLiteralTest.java
@@ -443,4 +443,17 @@ void testDateTimeV2Scale() {
                 new DateTimeV2Literal(DateTimeV2Type.of(5), "2016-12-31 23:59:59.999999"),
                 new DateTimeV2Literal("2017-01-01 00:00:00.0"));
     }
+
+    @Test
+    void testRoundFloor() {
+        DateTimeV2Literal literal;
+        literal = new DateTimeV2Literal(DateTimeV2Type.of(6), 2000, 2, 2, 2, 2, 2, 222222);
+        Assertions.assertEquals(222222, literal.roundFloor(6).microSecond);
+        Assertions.assertEquals(222220, literal.roundFloor(5).microSecond);
+        Assertions.assertEquals(222200, literal.roundFloor(4).microSecond);
+        Assertions.assertEquals(222000, literal.roundFloor(3).microSecond);
+        Assertions.assertEquals(220000, literal.roundFloor(2).microSecond);
+        Assertions.assertEquals(200000, literal.roundFloor(1).microSecond);
+        Assertions.assertEquals(0, literal.roundFloor(0).microSecond);
+    }
 }