The mathematical model of clutch combination process was established,and the clutch friction work in vehicle start process and the convective heat transfer coefficient of friction plate with air were calculated.The finite element model of the friction plate established and thermo-mechanical coupling analysis of the friction plate was performed.The results show that the highest temperature of friction plate reaches to 75.5 ℃ in the start process of vehicle.The friction surface temperature is gradually increased from the inner edge to the outer edge of friction plate.Maximum thermal deformation reaches 0.011 4 mm in the start process of vehicle.The friction plate heat distortion is radial expansion,axial waves warping.