Abstract: A lot of grade IV and V discontinuities distributed in the open-pit slope rock mass have great effect on the stability of rock mass. According to the characteristics of open-pit slope rock mass, a systematic analysis method is put forward. Firstly, a 3GSM contact-free measuring system is employed to capture the discontinuities outcropped in rock mass, and the probability model for geometric parameters of structural plane can be obtained. Then the fracture network is generated by means of the Monte Carlo method. Considering the size effects of REV, the permeability tensor of rock mass is calculated using the discrete medium seepage method, and the elasticity tensor of rock mass is obtained using the geometrical damage theory, and the rock mass parameters are finally determined. Finally, the anisotropic seepage-stress coupling model based on the equivalent continuum model is established for mechanical analysis of stability of slope rock mass by using COMSOL software. Moreover, the proposed method is applied in the southern slope of Fushun west open-pit mine, and the results agree with the failure observation well. The stability of slope rock mass can be evaluated by using the proposed method considering the characteristics of rock mass caused by distribution of joints. It is simple but very reasonable, and hence it has a good application prospect.