Aiming at the reactor noise problem caused by core vibration, a multi-physics field simulation method of magnetic field and structural mechanics is proposed for the reactor using COMSOL. The vibration mechanism and multi-physics field theory of the reactor are first analyzed, and then comparative vibration simulations with different excitations are carried out for the reactor considering magnetostriction (MS) and Maxwell force (MF). The flux density distribution is observed to be similar for both sinusoidal and SPWM excitation in the reactor model, with a maximum at the corners of the core and a sudden change at the air gap. As the flux density increases, the vibration displacement of the core also rises. The average vibration displacement of the reactor model under SPWM excitation is significantly greater compared to that under sinusoidal excitation. Increasing the modulation ratio can reduce vibration displacement by decreasing the harmonic content.