2-D tidal and sediment numerical model with triangular grids is set up to study the general planning scheme of Tonghai harbor area at Nantong port based on the Yangtze estuary waterway maintenance management platform “ SWEM2D / 3D”. According to the simulation results, the impacts of the general planning scheme on the nearby main waterways( main channel of Yangtze, Baimao channel, Beizhi channel, Xinkasha channel and Fushan channel) are analyzed. The numerical simulation result shows that current on the Xuliujing section is further strengthened after the implementation of the general planning scheme. The impact scope of the general planning scheme is about 1.5 km away from the harbor. The affect of wharf engineering to Sutong bridge is very small, and its main navigable hole will keep stable. The general planning scheme of Tonghai harbor area has little influence on the tidal force in the nearby main waterways, and the general planning scheme is feasible.