The basic principles of discrete element method and strength reduction method are introduced. The method of combining the 3DEC and strength reduction method is presented and applied to the stability analysis of a high slope of a hydropower station. The reduction coefficient in divergence stage of key points’ displacement-time curve is defined as the slope safety coefficient

and the critical slip surface and failure mode can be determined according to the velocity vector of a slope. Numerical results presented in the paper indicate that this method is reliable for jointed rock slope stability analysis compared with the Dijkstra limit equilibrium FEM and classical LEM method. For no considering the 3D initial ground stress field in 2D common SRM

based on the 2D analytical results

the 3D generalized geological model is set up to get the 3D stress field. According to the analysis of the stress distribution and the main problems in the project

the specific geological model with unit width is set up by the auxiliary joint in the 3DEC. Based on the 3D stress field

the SRM is carried out. The new method takes consideration of the influence of the 3D stress filed of the slope stability and bas made up the shortcoming of 2D common SRM. This method is a rational and efficient stability analysis method and is worth using in similar projects.