diff --git a/tests/system-test/1-insert/alter_table.py b/tests/system-test/1-insert/alter_table.py
index 6ae6febfe41152a4e0266e7f2f5389cb9a3ba2b5..fb5696f343147595e727cae23fd4d7e633f050d1 100644
--- a/tests/system-test/1-insert/alter_table.py
+++ b/tests/system-test/1-insert/alter_table.py
@@ -88,10 +88,10 @@ class TDTestCase:
         tdSql.checkData(0,15,tag_nchar)
 
         # bug TD-16211 insert length more than setting binary and nchar
-        # error_tag_binary = self.get_long_name(length=21, mode="letters")
-        # error_tag_nchar = self.get_long_name(length=21, mode="letters")
-        # tdSql.error(f'alter table {dbname}.{tbname} set tag t12 = "{error_tag_binary}"')
-        # tdSql.error(f'alter table {dbname}.{tbname} set tag t13 = "{error_tag_nchar}"')
+        error_tag_binary = self.get_long_name(length=21, mode="letters")
+        error_tag_nchar = self.get_long_name(length=21, mode="letters")
+        tdSql.error(f'alter table {dbname}.{tbname} set tag t12 = "{error_tag_binary}"')
+        tdSql.error(f'alter table {dbname}.{tbname} set tag t13 = "{error_tag_nchar}"')
 
         # bug TD-16210 modify binary to nchar
         tdSql.error(f'alter table {dbname}.{tbname} modify tag t12 nchar(10)')