Abstract:A generation algorithm of cover system for numerical manifold method(NMM) is introduced. This algorithm is based on the travel theory of the oriented graph and the formation of the block system is incised by the joints and fractures. By this algorithm combined with the adaptive generation technology for finite element method(FEM) mesh,the mathematics mesh is built,and then in the travel theory of the oriented graph,a final cover system for NMM can be efficiently formed. This method also provides a way to obtain the available element library for the FEM in the NMM based on existing FEM elements.