The stability analysis of rock slope has many places to be improved because the rock mass material has the characteristics of heterogeneity，anisotropy and discontinuity.In this paper，the relationship between the strength reduction factor of rock mass is studied theoretically.The results show that a single reduction factor method，which converts the double reduction factor method to one of the reduction coefficients，is realized，which greatly simplifies the operation of numerical simulation.In addition，this paper presents a dynamic strength double reduction factor method considering residual strength to dynamically observe the development of potential slip zones on the slopes.The research results show that it can solve the problem of slope stability prediction and provide the basis and basis for the design of rock slope engineering.