Taking the surface profile of C45 steel grinding as the research object, a two-dimensional finite element contact model of rough surface and smooth rigid surface was established by using ANSYS software, and the stress distribution characteristics and rules of contact surface were analyzed under 0–10 MPa normal load. On this basis, the force-magnetic coupling model was established by using ANSYS APDL language. Furthermore, the influence of stress under on leakage magnetic field of contact surface under different load conditions was studied. The results indicated that according to the zero-crossing point of the normal component of the leakage magnetic field or the extreme point of the tangential component, the number of stress concentrations on the contact surface and the stress level of the corresponding area can be effectively determined. This innovative approach offers valuable insights for future studies on surface contact stress distribution between components.