Abstract: Due to the characteristics of constant working resistance and steady large deformation, the NPR cable has been widely applied in monitoring and reinforcement of a large number of roadways. In order to study the anchorage effect of NPR cables in open-pit slope, firstly, the NPR cable element is developed based on the cable element in the finite difference software FLAC^3D, and it is proved by the tensile tests that the NPR cable has better energy absorbing capacity than the traditional one. Secondly, the second-order work criterion is then implemented, and the rationality and advantages of the second order work criterion as a safety factor in explicit numerical algorithm are discussed. Finally, the rock slope induced by the excavation at the north side of the west stope in Haoyaoerhudong Opencast Gold Ore is taken as the research object, and the stability of rock slope under the existing traditional mine cable support system and NPR cable support system is compared and analyzed. According to the numerical results, the global second-order work and kinetic energy of each loading step have the opposite variation tendency, and the slope stability of NPR cable support system is obviously better than that of the traditional mine cable.