Aiming at the problem of temperature rise of mine flameproof outer rotor permanent magnet synchronous motor, based on the fluid structure coupling method, the temperature distribution of motor under three cooling schemes of air cooling and water cooling are calculated respectively. For the structure I air cooling system, the influence of different number of heat sink on the maximum temperature rise and pressure drop of fluid channel is analyzed, and the parameters of heat sink are optimized. For the structure II air cooling system, the influence of setting fillet at the turn back of the fluid channel on the head loss in the fluid domain of the motor is analyzed, and the influence of different fillet radius on the head loss and the maximum temperature rise in the fluid domain is obtained. For the structure II water cooling system, the influence of different water flow speed on the maximum temperature rise of the motor is analyzed, and the influence of different assembly clearance of modular stator teeth and yoke on the maximum temperature rise of the motor is analyzed. The cooling effect and temperature rise distribution characteristics of the three cooling schemes are compared and analyzed. Finally, a water-cooled prototype is manufactured, and the temperature rise experiment is carried out, and the influence of the thermal deformation of fluid channel, stator yoke and stator teeth on the maximum temperature of the motor is analyzed. The results show that the calculated temperature field after considering the thermal deformation is closer to the experimental value, which verifies the accuracy of the calculation results, It also provides a reference for the selection and design of the cooling structure of the same type of PMSM electric roller.