Abstract: An electromagnetic vibration analysis method of motors is proposed in this paper, based on a quasi-3D electromagnetic field model and electromagnetic-structural bi-directional coupling. This method considers the influence of rotor axial eccentricity and end effects. First, a dynamic electromagnetic-structural bi-directional coupling model of the motor is established, and various excitation forces during the coupling calculation process are analyzed. Then, a quasi-3D electromagnetic field model is proposed, which simplifies the rotor axial eccentricity problem in axial segments, and takes the influence of the end effects into account with a modified function. Next, a method for initial mesh partitioning and mesh node labeling of the structural field and electromagnetic field is devised, facilitating the swift and precise transfer of parameters within the bi-directional coupling analyses of different physical fields, which is accomplished through a cyclic iterative calculation based on the quasi-3D electromagnetic field model. Finally, the electromagnetic vibration characteristics of a permanent magnet synchronous motor are quantitatively analyzed by using the electromagnetic vibration analysis method based on electromagnetic-structural bi-directional coupling, and experimental results confirm the accuracy of this method.