Abstract: Dumping at sea, as the main way to deal with the dredge produced by the construction of ports and waterways, plays a vital role in the development of marine economy. In order to further study the topographic changes and effects of the adjacent dump area on the surrounding dump area, a two-dimensional hydrodynamic model and a sediment model were established in this study. Through the detailed analysis of the simulation results of the dumping process of dredging materials, we calculated the change of water depth in the dumping area after the dumping of dredging materials in each dumping area, and compared it with the common dumping situation of multiple dumping areas under the same working condition. After joint dumping, the siltation thickness of the adjacent dumping area increases and the original capacity of the dumping area is limited. This study provides a scientific basis for the subsequent capacity assessment of multiple dumping areas, and is helpful to provide guidance for the rational planning and use of marine dumping areas.