Abstract: An elasto-plastic model of intact rock is established and added to the existing numerical manifold method (NMM) for deformation and strength analysis. The corresponding VC++ program is then developed. For verification, several load simulations of rock specimens are carried out. The computed results show a favorable agreement with either analytical or physical test results. Since the NMM has the inherent advantage in dealing with rock discontinuities, the new NMM program equipped with the capacity of elasto-plastic analysis can be an effective tool for more geotechnical projects. . The stability of a rock slope is analyzed with the program. In addition, rock bolts are taken into account in the simulation process. Different rock bolting design schemes are compared through the numerical simulation. The computed results offer the displacement field, the stress distribution and the evolution of plasticity, which show that rock bolts can prevent the joints in the slope from cracking and the prestressed bolts can efficiently restrict the evolution of plasticity. In addition, it is observed that rock bolts combine the rock blocks on both sides of the joint to deform consistently, enhancing the entirety of the rock slope.