What is the name of railway station from Beijing to Tianjin,what is the nearest metro station?

First of all, the bullet trains to Tianjin depart from South Railway Station. From the airport, it's not necessary for you to take metro. Just take direct shuttle bus line 10 to South Railway Station. The ticket fare is CNY 24 per person. The train takes around half an hour. The ticket fare of second class seat is CNY54.5, first class seat is CNY94.5 and business class seat is CNY174.5.

In addition, there is the other easier way for you to choose. You can catch the direct long-distance bus at airport and get to Tianjin Tianhuan Bus Station. The bus schedules are from 6:30 to 23:00. It costs CNY 82 per person. And the duration is about 2.5 hours.