I'll be coming to Tianjin port on 18 dec. we like to visit Great wall of china and good cheap shop.

But which section of Great Wall do you refer to? Anyway, the closest section is Huangyaguan. Go from the port to local Chengbei Long-distance Bus Station to take a direct bus to Jixian County. Thereafter, transfer to a direct bus or van at the station to the wall. As for cheap shopping in TJ, I suggest you go to the Ancient Cultural Street for a try.