pls let me know how to travel from pudong airport to keqiao city?

Well, there is no direct long-distance bus at the airport that can take you to Keqiao.
Upon landing, you can take airport shuttle bus line 7, get off at South Railway Station first. Then walk southeast around 800 yards to arrive at South Bus Station.
There are two long-distance bus at 08:19 and 13:05 that can get to Keqiao. The ticket fare is CNY 75 to 80 per person.