Abstract: Flywheel energy storage systems usually operate under high-speed, high-power-density, and rapid charge-discharge conditions, where internal motor losses and temperature rise directly affect system efficiency and reliability. To address the problems of high thermal load, complex loss distribution, and obvious local temperature rise in the Axial Three-Phase Spherical Bearingless Flywheel Machine (ATPS-BFM) under high-power rapid charge-discharge conditions, this paper carries out loss calculation and magneto-thermal coupling temperature field analysis. Based on the analysis of the basic structure and operating principle of the motor, an electromagnetic loss model including hysteresis loss, eddy current loss, and additional loss is established. Furthermore, the temperature rise distribution of the ATPS-BFM is investigated through magneto-thermal coupling finite element simulation. The results can provide a reference for heat dissipation design, structural optimization, and material selection of this type of motor.