You can take a bus from Tongzhou Beiguan subway station to Baoxiao South Street in Songzhuang. According to the relevant public information, Tongzhou Beiguan Metro can take Bus No.2 to Songzhuang, and the specific route is as follows:

1. Walk 466 meters from Tongzhou Beiguan subway station to Huangmuchang bus station.

2. Take bus No.2 bound for Haogezhuang Village, get off at the bus stop at the south exit of Baoxiao Village, and after 7 stops, walk 388 meters to the destination Xiaonanbao Street in Songzhuang.