Due to the space limitation of the working place, the interior permanent magnet synchronous motor(IPMSM) for compressors has higher requirements on the power density and its temperature rise has become an urgent problem to be solved. Taking a 7.5 kW IPMSM as an example, the axial ventilation cooling structure is designed and analyzed based on computational fluid dynamics(CFD) and fluid-solid coupling heat transfer theory.The fluid flow characteristics inside the motor are analyzed under the condition that the casing has ventilation slots and the rotor is installed with wafters and ventilation vents. The influence of the number of air inlets on fluid flow is studied. The temperature rise distribution of each part of the motor is obtained. The effects of wafters and number of air inlets on the heat dissipation of the motor are compared. Finally, a 12-pole 54-slot axial ventilation IPMSM is manufactured, and the effectiveness of this cooling structure is verified by the experimental data of prototype.