Abstract: The prediction model of propagation life of oblique crack on rail′s surface was established by the fracture mechanics theory. Taking CRH2 train-set as research object, stress distribution in the internal of rail when wheel and rail contacted was calculated, and then the propogation life of oblique crack on rail surface was estimated by using above modle. Furthermore, the effects of friction factor, inclination angle and wear rate on the propagation life of rail surface oblique crack were analyzed. The results show that the oblique crack propagation life decreased with the increase of friction factor when the inclination was 30°-40°, and the oblique crack propagation life first increased then decreased when the inclination angle was 50°-60°. With the increase of inclination angles, the oblique crack propagation life increased, then decreased. The oblique crack propagation life increased slowly with the increase of wear rate, and then increased rapidly when the wear rate up to a constant value. Fact data could prove indirectly the accurate of prediction.