Abstract: Taking the slope of A Engineer for example,the dynamic response and failure mechanism of slope rock mass under seismic loading are simulated by FLAC2D.The time-history curve of artificially synthetic acceleration is used.The following results are obtained: under the seismic dynamic load,the side slope could form a large deformation(greater than 3.0m),the plastic zone is distributed between the capping and the interface of the bedrock,the rock and soil of the interface can form a plastic collapse,causing a long-distance landslide,so the comprehensive control measures must be taken.This conclusion has important application value for the selection and construction of the repository.