Abstract: The volume of RS accumulation of RM hydropower station is as large as 47 million m³, which is huge and close to the dam site. In the process of reservoir impoundment, the physical and mechanical parameters of the slope are reduced due to the hydrodynamic effect, which may cause instability and damage to the safety of the project. In this study, the rigid body limit equilibrium method, virtual power method, finite difference method, finite element strength reduction method and three-dimensional numerical simulation are used to analyze the stability and catastrophe process of RS accumulation body. The results show that the slope is basically stable in the natural state, and the possibility of edge stability and instability is great with the rise of water level in the process of water storage. The state of slope stability changes from the process of stability- deformation→local instability large→scale instability→largest→scale instability to the catastrophic process. The simulation reveals the generating process and propagation law of surge under instability, and its risk is analyzed. The research results can provide a meaningful reference for similar engineering problems.