Abstract: Impact failure of rock is a kind of typical dynamic problem.In order to perfectly analyze the dynamic problem by use of numerical manifold method(NMM),the Newmark method of dynamic finite element method was adopted to improve the algorithm in original NMM on the basis of analyzing the solution idea of dynamics problem in NMM.There were three obvious advantages in the improved method over the original one: ①The solution of this method was convergent without any condition when suitable parameters were selected;②The time step adopted in this method was much longer than that in the original one;③The damping effect in the dynamic problem was fully considered.In the end,a calculation example was used to illustrate the application of this method in simulation of the whole process of impact failure of rock,which overcame the shortcomings of FEM in simulating the block movement after rock failure.