There is a magnetic field inside of the radial bearing. The magnetic field distribution is one of the key factors that decides the running state and performance of the system. By using the finite element ANSYS software, the magnetic field of radial bearing was analyzed. The analysis indicated that NSSN mode is suiTable for magnetic radial bearing and NSNS mode unsuiTable. There is a magnetic coupling between magnetic poles. There is magnetic leakage for radial bearing, which leaks towards spindle center through rotor and to coil, but it is very little, less than 5%. The research provides a theoretical basis for optimization of system structure and controller design.