According to the feature of gravity quay and project area, a two-dimensional horizontal current-sediment numerical model is established and verified by the measured data. The model is used to analyze the impact of gravity quay on the hydrodynamic of Dongshan bay and sediment conditions and provide the basis for site selection and program layout. The result shows that the tide current field in Dongshan bay has little change and changes mainly locates around the project. The suspended sediment increment scope is concentrated at the east side of the project. The range of siltation is small, and the maximum siltation intensity is 12 cm/a. Overall, the siting and design of the project are feasible.