diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/TimestampArithmetic.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/TimestampArithmetic.java
index 888a1a0869ccbb..d3e326fa48a574 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/TimestampArithmetic.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/TimestampArithmetic.java
@@ -160,6 +160,7 @@ public boolean equals(Object o) {
         }
         TimestampArithmetic other = (TimestampArithmetic) o;
         return Objects.equals(funcName, other.funcName) && Objects.equals(timeUnit, other.timeUnit)
+                && op.equals(other.op)
                 && Objects.equals(left(), other.left()) && Objects.equals(right(), other.right());
     }
 }