The strength of the gear pair in the high-speed train gearbox is a key factor for the safe operation of the train, using China’s independent research and development high-speed train bogie gearbox gear as study object, three-dimensional gear system model was established, and finite element model was built by SOLIDWORKS simplifying, and with ANSYS WORKBENCH, static and transient mechanical analysis of gear meshing parts was carried out. Theoretical calculation and simulation results were both within the safe range of strength, and met the designed requirements. In transient dynamics analysis, it was found that there was some higher contact stress and stress fluctuation at the starting stage of the gear, which would have some adverse effects on the reliability of the gear system.