Abstract: Some theories on physical mechanism of metal magnetic memory testing were studied.The influences of load-unload velocity on stress-magnetic effect at geomagnetism field,environmental magnetic field on stress-magnetic effect and environmental magnetic field on stress-strain were researched.The theories of strain-magnetic under stress,equivalent of stress versus magnetic field and energy balance at the action of stress were analyzed.Ishows that electromagnetism induction principle for stress-strain at geomagnetism field has little influence on stress-magnetic effect,environment magnetic field is related to the stress-magnetic effect,environment magnetic field has no relation with stress-strain.Stress-magnetic effect is the acting result of stress and environment field,and is caused by the influence of stress on microstructure and magnetic domain characteristic of materials.