How go to tianjin beach from airport?

Without knowing which beach you are referring to, here is the way to Dongjiang Bay Beach, which is a man-made beach:
take subway line 2 from the airport to TJ Railway Station. Transfer to light rail line 9 to Civic Square. Upon getting off, take bus no. 513 to the beach directly and the dropping-off stop is Dongjiangwan Jingqu.
By taxi, it may cost CNY120-150.