Hello sir,I want to know how to reach Shanghai hongqiao airport t2 to south city bus station by metro train?

You mean you want to reach T2 of Hongqiao Airport from the south bus station, right?
If so, you can walk to the SH South Railway Station to take the local subway line 1 to reach South Shaanxi Road Station, where you can change to line 10 to reach Hongqiao Airport T2 Station.