Abstract: The stability of rock slope under the effect of earthquake plays a significant role in slope stability study, which is difficult to analyze. The paper, based on the engineering geological conditions in the area where the hydropower station is to be located, analyzed the dynamic stability of the slope in combination with engineering geology analysis. Then a numerical model was built based on real condition, and the analysis of the stability of the slope under earthquake action was conducted with finite difference program FLAC 3D. Through comparison, the results of numerical simulation verified the correctness of the conclusions of engineering geology analysis, and provided evidence for the design and construction of the hydropower station, also provided ideas for the similar slope seismic stability evaluation.