Based on the electromagnetic thermal coupling analysis method, the cooling performance of different motor cooling models and the influence of key parameters of the cooling system on the cooling effect of the motor are investigated. First, the losses of various parts of the permanent magnet synchronous motors are obtained through electromagnetic calculations; the analysis results show that the stator core loss, winding copper loss, and eddy current loss of permanent magnets exceed 95% of the total loss of the motor. Second, the cooling performance of the three motor was compared and analyzed. The axial housing liquid cooling and oil spray cooling (Model B) has a better cooling performance and a higher cooling efficiency. Compared with the other two motor models, Model B can reduce the time to reach steady-state temperature by about 81.8%.Then the effects of coolant volume flow rate, coolant inlet temperature, and ambient temperature on the cooling effect of the motor are investi-gated. The results show that within a certain range, the rate of coolant inlet temperature change is approximately proportional to the internal temperature rise of the motor. The oil spray cooling system of Model B is less affected by ambient temperature and can be used for motor cooling in complex environments. The results of this study can provide a useful guidance for the design of the cooling system and the selection of coolant volume flow rate for oil-cooling motor with hairpin windings.