Considering the material nonlinearity,geometric nonlinearity and contact nonlinearity involved in the use of rubber lip seals into the axisymmetric finite element model,the friction heat buildup between the seal and the highspeed rotating shaft was numerically simulated by the mechanicalthermal field coupling method,and compared with the experimental results of lip seal testing device and the temperature measured by infrared imager.The simulated friction torque and lip temperature are in good agreement with the experimental results,showing that the mechanicalthermal field coupling method can predict the shaft holding force and friction torque of oil seal,as well as the temperature field of friction heat buildup in steady state,which provides an effective way to simulate and analyze the friction heat buildup of similar rotary seals.