The Xiaoshi shipping hub is the last step of the Tuojiang River Basin. According to sediment data from Lijiawan（Fushun） hydrological station，this paper calculates and analyzes the sediment deposition in the reservoir area. Based on the existing data，the paper studies the riverbed evolution and the causes of deposition and uses a one-dimensional hydrodynamic calculation model to calculate water surface lines before and after reservoir construction，with the backwater effect of the Yangtze River being absent or present. The results show that the deposition phenomenon of some cross sections is serious. The channel is scoured and silted，and its shape form is basically stable. The water surface slope under the backwater effect is significantly less than that under natural conditions，and the impact of the flood backwater effect is significantly smaller in front of the dam than the tail of the dam.