In two elastic bodies that acts rolling/sliding contacts，it's well-known that follower side is apt to cause fracture than driver side. So trying to infinite the radius of curvature in follower side，this report consider the semi-infinite case and the initial cracking case. The former of this report compare the calculation results by finite element method with boundary element method. The latter of this report analyze the stress of initial cracking by boundary element method，and study propagation behavior of initial cracking.