Abstract: The service loads of hollow axles of high speed train were defined, and the stress of hollow axles were obtained by calculating the load spectrum. Quarter point 20-node isoparametric degenerate singular elements are used in modeling the region near the crack tip, The finite element model of crack extension of hollow axle is created, and the crack front is dispersed to simulate orthogonal extension. Then, the stress intensity factors of crack front are calculated. Finally, the distribution rules of the stress intensity factors of different initial crack shapes are presented, which agree well with the analytical results.