At present,there are still some deficiencies in the method of slope stability analysis under the present dynamic interaction. For examples, the dynamic problem was treated as a static problem, dynamic effect under loading seismic wave was not fully considered, only shear failure was considered, and the gradual failure process of the forming of slope sliding surface was not considered, etc. Therefore, both the reduction of slope shear strength parameters and slope progressive failure process would be considered in this paper. Combined with the dynamic finite element strength reduction principle and slope instability criterion, the slope dynamic stability safety factor and the tensile and shear failure surface were both determined from the monitoring point displacement and acceleration mutation, the convergence of numerical, and the penetration of tensile and shear failure surface. The results showed that, the dynamic finite element strength reduction method evaluated the rock slope stability under seismic action quantitatively and effectively, and fully reflected the gradual failure process. The results can provide references for seismic design of rock slope under seismic action and dynamic stability analysis.