Abstract: The Extended Finite Element Method (XFEM), which is based on the partition of unitym, is a novel numerical approach to solve discontinuous problems. It employs jump function and asymptotic crack tip displacement field function in Classical Finite Element Method, and applies the Level Set algorithm to describe the crack interface and judge the element types. It can be used to analyze the problem of material fracture. Compared with the classical finite element method, where the finite element mesh and the location of crack are mutual independent, the XFEM does not need to construct a mesh which conforms to the crack surface, and thus achieves fine granularity partition around the crack tip. The results from the case analysis demonstrate the impact of the scheme of element integration and the integral region of crack tip on the calculation accuracy of stress intensity factor.