diff --git a/cdc/sink/codec/internal/column.go b/cdc/sink/codec/internal/column.go
index 35ca589d129..77340506be0 100644
--- a/cdc/sink/codec/internal/column.go
+++ b/cdc/sink/codec/internal/column.go
@@ -94,8 +94,10 @@ func (c *Column) ToRowChangeColumn(name string) *model.Column {
 			if err != nil {
 				log.Panic("invalid column value, please report a bug", zap.Any("col", c), zap.Error(err))
 			}
+			col.Value = []byte(str)
+		} else {
+			col.Value = str
 		}
-		col.Value = str
 	default:
 		col.Value = c.Value
 	}
diff --git a/cdc/sink/codec/open/open_protocol_message_test.go b/cdc/sink/codec/open/open_protocol_message_test.go
index 826eda172f7..d29f7654b14 100644
--- a/cdc/sink/codec/open/open_protocol_message_test.go
+++ b/cdc/sink/codec/open/open_protocol_message_test.go
@@ -65,7 +65,6 @@ func TestNonBinaryStringCol(t *testing.T) {
 	require.Equal(t, row, row2)
 	mqCol2 := row2.Update["test"]
 	col2 := mqCol2.ToRowChangeColumn("test")
-	col2.Value = string(col2.Value.([]byte))
 	require.Equal(t, col, col2)
 }