Abstract: The short-time duty permanent magnet motor with high power density has the characteristics of high current density and high temperature rise of armature winding. The accurate calculation of the 3D temperature field is huge important to the design of high power density motor. Firstly, the loss of high power density motor was calculated carefully, and the resistance and copper loss of end winding were also analyzed especially. Secondly, in the calculation model of the 3D temperature field, a layered equivalent model of the armature-winding end was defined and the experimental results show that the layered equivalent model can improve the accuracy of the winding temperature calculation. Thirdly, in order to reduce the winding-temperature rise of high power density motor, we chose a technique for optimizing the heat conduction of the winding end, which can reduce the thermal resistance between the winding end and the housing. Then the highest temperature of winding dropped from 80 degrees to 69 degrees on the Celsius scale. Finally, the correctness of the theoretical calculation is verified by the prototype experiments.