This paper analyzed the variation tendency of hydrological elements such as tidal level, tidal range, tidal time from three main hydrology stations （Luchaogang, baozhen and Gaoqiao tide stations ） in coastal area of shanghai, and got the conclusion that tidal in coastal area of shanghai is mainly controlled by factors such as sea level rise and floods at the upper river. The trend of mean tide level change is as same as the trend of sea level rise. Hangzhou bay's tidal range turns to increase, but the range of north channel of Changjiang Estuary turns to decrease. Moreover, the flood tidal time increases in hangzhou bay. It also analyzed the possible influence.