diff --git a/internal/datanode/compactor.go b/internal/datanode/compactor.go
index 04c925fbd7..f482194355 100644
--- a/internal/datanode/compactor.go
+++ b/internal/datanode/compactor.go
@@ -162,6 +162,9 @@ func (t *compactionTask) mergeDeltalogs(dBlobs map[UniqueID][]*Blob) (map[interf
 		for i := int64(0); i < dData.RowCount; i++ {
 			pk := dData.Pks[i]
 			ts := dData.Tss[i]
+			if lastTS, ok := pk2ts[pk.GetValue()]; ok && lastTS > ts {
+				ts = lastTS
+			}
 
 			pk2ts[pk.GetValue()] = ts
 		}
diff --git a/internal/datanode/compactor_test.go b/internal/datanode/compactor_test.go
index e224934e66..37274a80e4 100644
--- a/internal/datanode/compactor_test.go
+++ b/internal/datanode/compactor_test.go
@@ -197,6 +197,7 @@ func TestCompactionTaskInnerMethods(t *testing.T) {
 					4,
 					5,
 					1,
+					2,
 				},
 				[]Timestamp{
 					20000,
@@ -205,6 +206,7 @@ func TestCompactionTaskInnerMethods(t *testing.T) {
 					30000,
 					50000,
 					50000,
+					10000,
 				})
 			require.NoError(t, err)
 
@@ -232,6 +234,7 @@ func TestCompactionTaskInnerMethods(t *testing.T) {
 					if test.isvalid {
 						assert.NoError(t, err)
 						assert.Equal(t, 5, len(pk2ts))
+						assert.EqualValues(t, 20001, pk2ts[UniqueID(2)])
 					} else {
 						assert.Error(t, err)
 						assert.Nil(t, pk2ts)