In order to effectively improve the numerical calculation accuracy of transformer core vibration and reveal the influence mechanism of mechanical behavior on transformer core vibration, a magnetic-mechanical coupling characteristic modeling and vibration numerical calculation method of transformer core considering clamping force and friction is proposed. The nonlinear relationship between the clamping force and the friction force is quantified from the microscopic scale, and the dynamic rolling direction contact stiffness of the joint surface is obtained, and the friction contact model of the clamp-insulation-core structure is constructed. Based on the mechanical-electrical analogy theory, an equivalent vibration circuit model that can describe the vibration of transformer core under different clamping forces is established, and the accurate calculation of vibration is realized by numerical simulation method. Compared with the calculation results without considering friction, the vibration displacement calculation results considering the influence of friction are closer to the actual experimental measurement values.