Aiming at the problem that seasonal runoff has a great impact on the hydrodynamic conditions in the estuary area，the variation of water and sediment characteristics in flood and dry seasons of Wugang Wharf，Taicang in the Yangtze River is studied.We compare the test data of tide level，tidal current，sediment concentration，suspended load and sediment in flood and dry seasons of Wugang Wharf，Taicang from 2018 to 2019 by prototype observation method，and analyze the changes of water and sediment characteristics in flood and dry seasons in the project area.The results show that the change of tidal level in the project area is obviously affected by runoff；The project area is a typical reciprocating flow，and the fluctuation trend is basically the same in flood and dry seasons；During the hydrological test，the sediment concentration in dry season is slightly lower than that in flood season，and the difference range is 5.88%～25.67%；The median particle size of suspended load in flood and dry seasons is basically the same；The bottom material is mainly composed of cohesive silt，cohesive soil and fine sand.