Abstract: Rockmass is a kind of typically complicated structure body with continuous and discontinuous media, and how to simulate the rock failure rule under impact loading is always a hotspot task in numerical simulation research. The Finite Element Method that regards rockmass as a continuous media body, the Discontinuous Element Method and DDA that regards rockmass as a completely discrete body do not either accurately reflects the failure characteristics. The numerical manifold method developed in recent years is a good method, which can simulate the failure behavior of the rockmass. Based on the basic theory of the numerical manifold method, the numerical simulation analysis is made to ascertain the influence of the discontinuous face such as joint, crack and so on on the rock rupture effect. The calculation result shows that numerical manifold method is accurate and effective in simulating this kind of problems.