Abstract: Supported by the data of surface sediment grain size, beach profiles and topographic surveys in different periods, we studied the surface sediment distribution pattern, beach profiles and water depth changes in the Jiulong Bay. The alongshore silt discharge rate of the study area was calculated, and the relationship between the hydrodynamic environment and sediment transport trend studied. The result shows that, the grain size of surface sediment is getting smaller from the coast to the offshore, the beach belongs to the typical offshore sediment transporting type and the wave is the main factor shaping the beach profile. Being influenced by the wave from north, the alongshore silt discharge moves southeastward.