The adjustment of the water level in the Three Gorges Reservoir area continuously affects the geological conditions along the coast. Coastal wading landslides and collapsed bodies are seriously deformed. In order to analyze the effects of water level changes and rainfall on the coast, the Xintian collapsed bodies are taken as the research object. Through on-site geological survey and engineering surveys, A calculation model of the collapsed body was established, and numerical simulation methods were used to analyze the deformation and failure of the collapsed body under the conditions of reservoir water level changes, rainfall and the coupling of the two. The Morgenstern-Prince method was used to analyze the Xintian collapsed body in the two-dimensional model. Carry out stability calculations under different working conditions, and establish a three-dimensional collapse model to further study the failure mechanism of collapsed bodies. In the numerical simulation, the changes of stress, displacement, pore water pressure and equivalent plastic strain are monitored. The results show that: Simultaneous rainfall has a great influence on the deformation of the collapsed body in Xintian. At the same time, under the most unfavorable conditions, the numerical prediction model of the deformation and failure of the collapsed body is established by using the calculation results to provide a reference for the later prevention and control of the collapsed body.