Switched Reluctance Motor (SRM) can be used in the field of flywheel batteries due to its simple topology, high efficiency and small size. The accurate analysis of the temperature field of the motor under high vacuum conditions is critical to the service life and safety performance of the flywheel system. important. Taking 12/8 SRM as an example, a two-dimensional finite element analysis model is built to analyze the typical position magnetic density of each component. The calculation model of iron loss is introduced and the calculation result is verified by finite element method. Furthermore, the magnetic-thermal unidirectional coupling method is used to analyze the temperature field of SRM under high vacuum condition, and the temperature distribution of each main component of the motor is analyzed, which provides a reference for temperature prediction and heat dissipation design of SRM for flywheel battery.