Abstract: The dynamic response and failure mode of earth rockfill dam under earthquake is always a research hotspot in geotechnical engineering. FLAC finite difference software is used to analyze the residual deformation,acceleration response and shear strain of Shanmei earth rock dam after earthquake,and the general dynamic response law of Shanmei earth rock dam is obtained. By changing the upstream water level,the evolution mode of plastic shear strain area in the dam during the earthquake and the residual strain pattern in the dam after the earthquake at different water levels are described. It is found that the shear strain concentration position of Shanmei Earth Rock Dam is generally at the junction of different dam materials at the dam crest and dam slope. The shear strain pattern in the dam is basically unchanged after a stationary earthquake,but the shear strain is continuously accumulated,In addition,the gradual elevation of water level will lead to the formation of a plastic discontinuous shear zone in the upstream dam material after the earthquake. This study helps to understand the cause and formation process of plastic shear strain zone of Shanmei Earth Rock Dam under earthquake action,and can provide an important reference for the seismic work of Shanmei Earth Rock Dam.