Abstract: Based on the calculation of the tide and sediment data measured in the Xinghua bay by use of the mechanism decomposition method, the characteristics of the suspended sediment transport in the Xinghua bay have been illustrated through exploring the mechanism of the advection, tidal pumping effects and the vertical circulation for sediment transport, and the impacts of the sediment transport on the topographic changes in the study area have been discussed in this paper. The analysis results show: offshore sediment moves toward the inner of the bay along the Xinghua and Nanri channels under the action of tide, but it has little influence on the sedimentation in the inner of the bay. The advection and the vertical circulation are the primary factors for the suspended sediment transport, and the sediment transport in the deeper region is mainly controlled by the advection while the vertical circulation has a stronger impact in the shallow regions. The sediment transport under tidal pumping effect is dominated by the correlation between the suspended sediment and the tidal current, which is less than the sediment transport caused by the advection and the vertical circulation. The residual current directions are inconsistent in different vertical layers in the shallow estuary region, which causes the suspended sediment to mix well. The directions of the residual current in the surface and bottom layers are basically the same in the deeper region, and the vertical sediment concentration changes significantly. The deposition in the top of the bay is caused by the sediment transport. The main cause of the changes in the gulf topography is terrigenous sediment.