Based on the thermal elastohydrodynamic lubrication(EHL) theory,the lubrication characteristics of spiral bevel gear with high speed and heavy load were analyzed.The variation of two-dimensional profile curves of various characteristics (pressure,film thickness and temperature rise) of bevel gear oil film under different working conditions was studied.The results show that the combination of Hertz pressure peak and secondary pressure peak occurs under the condition of high speed and heavy load,and the classical flat phenomenon of central oil film in EHL is not significant.Only when the temperature decreases and the viscosity of the lubricating oil increases,the flat phenomenon of central oil film gradually appears.In order to improve the lubrication performance of gears by adjusting working condition parameters in engineering practice,the sensitivity of oil film characteristic parameters to input parameters was analyzed.It is found that the influence degree of working condition parameters on the maximum pressure of oil film is in order of elastic modulus,viscosity,rotational speed and power,the influence degree of working condition parameters on the maximum temperature rise and minimum thickness of oil film is in order of viscosity,rotational speed,elastic modulus and power.