Abstract: In order to reduce the difficulty of magnetization of traditional permanent magnet motors, an 8-pole 48-slot built-in permanent magnet synchronous motor for trucks is taken as the research object, a magnetization bridge structure is proposed, the corresponding magnetic network model is constructed, and the mathematical model under different working conditions is established according to the magnetic network model, which is compared and verified with the results of the Maxwell finite-element simulation calculations, and the verification results show the correctness of the mathematical model of the motor. By analyzing the magnetization mechanism, finite element parametric analysis of the structure and dimensions of the magnetization bridge is carried out to study its effect on the air-gap magnetism. The response surface method is used to optimize the regulator bridge structure with multi-parameter combination to find the optimal parameters of the regulator bridge structure, and the finite element model is established based on the optimized parameters for analysis. The results show that the magnetizing ability of the structure is improved from 13.1% to 30.1% in the magnetizing state and from 19.5% to 32.3% in the demagnetizing state. There is a significant improvement in the magnetizing ability, which verifies the rationality and effectiveness of the structure.