Taking a 315kW, 6kV permanent magnet synchronous motor (PMSM) with solid rotor as an example, the physical and mathematical models of PMSM three dimensional temperature fields analysis are established according to the heat transfer principles. The basic hypothesis and boundary value problems of the solving region in the motor are also presented. The 3-D temperature field in stator of PMSM was calculated, and the influences of heat transfer coefficients with consideration of the axial wind or not on stator temperature were analyzed. By comparing the test results with the calculated results, the influences of axial wind on motor temperature were investigated. These conclusions provide a reference for thermal design of the motor with co-axial fan and enclosure cooling fan.