High-speed motors will generate large core losses when running at high frequencies. In this paper, a high-speed axial flux permanent magnet synchronous motor(HSAFPM) is designed and developed. The stator material is selected from 0.05mm ultra-thin non-oriented electrical steel, which effectively reduces the loss of the motor core. In addition, the high-speed motor will generate a large amount of heat during operation, and the stator of the axial flux motor is generally wound from electrical steel. Based on the above conditions, the magnetic properties of electrical steel under the "bending stress-temperature-electromagnetic" multi-physics coupling are experimentally analyzed, and an iron loss model considering the influence of multi-physical fields is proposed. Experiments have verified that the iron loss model considering multi-physics coupling is more accurate than the classical eddy current loss model.