The drive motor for the vacuum pump has the engineering problem of the accumulation of thermal expansion of the rotor during the rated operation. According to the actual driving conditions of the vacuum pump, a flux switching stator permanent magnet synchronous motor (FSPMSM) is designed. The electromagnetic field, the temperature field and the thermal stress field of FSPMSM, surface permanent magnet synchronous motor (SPMSM) and interior permanent magnet synchronous motor (IPMSM) with the same technical requirements are compared and analyzed using finite element software. Comprehensive analysis of the performance differences of the three types of motors shows that the temperature rise and the thermal deformation of the FSPMSM are better than the rotor permanent magnet motor. It is verified that FSPMSM can better reduce the rotor loss and temperature rise during operation compared with the traditional rotor permanent magnet motor, which provides a scientific reference for the choice of topology of permanent magnet motor and the development of new products.