In order to found the reason for the raceway stripping of tapered roller bearing of high-speed EMUs gearbox, physical and chemical testing as well as geometric analysis of failure bearing were carried out, and rolling contact fatigue was determined to be the root reason of damage, which indicated the fact that the lubrication was insufficient during bearing working process. A mechanical model of roller and raceway was established, and the contact deformation was analyzed between roller and raceway. The bearing movement status was simulated and verified with bearing dynamic simulation software developed by SCHAEFFLER company, and the self-rotating effect of roller and the instant contact area between roller and raceway had been simulated, which illuminated that contact damage between tapered roller and raceway was mainly caused by insufficient lubrication.