In order to further study the nonlinear characteristics of the resonance magnetoelectric coefficient and vibration mode at the resonance frequency, three-layer magnetoelectric composite with length direction magnetization and thickness direction polarization is investigated in the article. Firstly, based on the Z-L model and the numerical solution characteristics of magnetization intensity, the magnetization intensity function was fitted, and the dynamic parameters of the giant magnetostrictive material, including dynamic piezomagnetic coefficient, dynamic elastic compliance coefficient, and dynamic magnetic permeability, were further derived. The effects of bias magnetic field and prestress on the corresponding composite were analyzed; Secondly, based on the nonlinear magnetostrictive constitutive equation, a symmetric magneto-elastic-electric equivalent circuit model of magnetoelectric laminate composite was established, and the expression of magnetoelectric coefficient was derived. The variation curve with bias magnetic field and prestress was analyzed, which is consistent with the conclusions of existing literature [8] and [9]; Finally, in order to compare with the theoretical results, the same parameters were set using COMSOL software, and the corresponding magnetoelectric coefficient frequency curve was plotted. The two results were in good agreement, and the maximum peak modal vibration shape was extracted, which can conveniently observe the vibration of the magneto electric laminate composite in the length direction. The results indicate that the theoretical model of this symmetric magneto-elastic-electric equivalent circuit and the numerical simulation method using COMSOL software are feasible, laying the foundation for further nonlinear analysis of magnetoelectric laminate composite and making it possible to design high-precision magnetoelectric micro devices.