Abstract: For ferromagnetic materials, distinct macro magnetism can be found under the stress ac tion even without the outside magnetic field. It is related to the irreversible change of the magnetic domain caused by the deformation and damage of structures. In this article, medium caxbon steel is tested and the hysteresis loop is achieved. By observing the curve of coercive force versus residual strain and the curve of residual strain versus rema nence) we have studied the coupled function of the strain and magnetic...