Abstract: A new enrichment scheme of crack tip is proposed in the framework of extended finite element method. In the new enrichment scheme, the characteristic of enriched functions are preserved by combining the traditional function basis, and only two additional degrees of freedom are added at each node of the crack tip element to improve the computational efficiency and reduce the matrix size. The inertia effect is considered by using the lumped mass matrix, and explicit time algorithm is adopted to research the problem of stable crack with dynamic loading. The values of dynamic stress intensity factors are computed by the interaction integral approach. The numerical results show that the new enrichment scheme is effective, and the feasibility and accuracy of simulating the dynamic response of the structure by explicit time algorithm is verified.