diff --git a/tests/system-test/2-query/To_iso8601.py b/tests/system-test/2-query/To_iso8601.py
index 16db0cca5913ecc5f7fae70b4d0e57bcf56cf70c..a8ab3e1a290ce768e39e130d2bb97d4ff5ce70a4 100644
--- a/tests/system-test/2-query/To_iso8601.py
+++ b/tests/system-test/2-query/To_iso8601.py
@@ -21,6 +21,7 @@ class TDTestCase:
     def check_customize_param_ms(self):
 
         time_zone = time.strftime('%z')
+        tdSql.execute(f'drop database if exists {self.dbname}')
         tdSql.execute(f'create database {self.dbname} precision "ms"')
         tdSql.execute(f'use {self.dbname}')
         tdSql.execute(f'create table if not exists {self.ntbname}(ts timestamp, c1 int, c2 timestamp)')