Abstract: For the characteristics of a high temperature and difficulty in heat dissipation of the winding end of a vehicle permanent magnet synchronous motor, this paper calculates the temperature rise characteristics of the motor under oil-water compound cooling conditions by adding an oil injection pipe to the end of the motor winding. The effects of water cooling and oil-water compound cooling on temperature rise characteristics of a permanent magnet synchronous motor are studied. The findings indicate that, when combined with an oil injection pipe at the winding end, the oil-water compound cooling strategy significantly cools the motor. The maximum temperature of the motor winding significantly reduces, and the temperature difference between high and low temperature zones is small, which plays a good role in temperature balancing. Besides, under the two rated operating conditions, compared with the water cooling scheme, the maximum temperature of the motor reduces by 27 ℃ in the oil-water compound cooling, with an improved cooling effect of 20% and 19% respectively.