Sheyang Port is located in the silty shoal in northern Jiangsu,with relatively poor water depth condition and strong silting intensity.In this paper,a two-dimensional tidal flow mathematical model is constructed to study the process of water transport capacity from the current situation to dredging to the design of the bottom elevation.The results show that with the waterway dredging deepen,the overall water velocity in the waterway shows a decreasing trend.The degree of decrease of water velocity is proportional to the dredging depth of the waterway.The maximum decrease of the rising jet is 43.4%~61.7%,and the maximum decrease of the falling jet is 39.8%~58.5%.When the dredging depth of the waterway is 6.5 m,the transport capacity of the waterway falling tide decreases by 40%~80%.When the dredging depth of the waterway is 10.5 m,the transport capacity of the waterway falling tide decreases by 80%~95%.The transport capacity of the waterway rising tide is stronger than that of the falling tide,which increases by about 80% compared with the current situation.When the surrounding sediment entered the waterway,it is not conducive to the outward transport of sediment.