How to get to Guanzhuang by subway from Beijing South Railway Station?

Take bus 20 → 639. According to Baidu map, it takes 2 hours 10 minute to take bus No.20 → No.639 from Beijing South Railway Station to Guanzhuang. The specific bus routes are as follows:

1. First, take bus No.20 at Beijing South Railway Station and get off at Beijing East Railway Station.

2. Secondly, take bus No.639 from Beijing Railway Station East Station and get off at Guanzhuang Road North Station.

3. Finally, walk 60 meters to Guanzhuang.