If I want to go Beijing railway station by tuanjihu. So how can I go there

You just refer to Tuanjiehu, right? And do you wanna travel there from the train station? Well, you can travel by bus or subway:

By bus: walk to BJ Station, Qianjie Station to take bus no. 673 to get off at Baijiazhuang, which is within 400m from Tuanjiehu.

By metro: take line 2 at the train station to Jianguomen, where transfer to line 1 to Guomao. then transfer to line 10 to Tuanjiehu.