In order to explore the quantitative method of metal magnetic memory testing(MMMT) and clarify the relationship between H_p(y),the normal component of spontaneous stray field,and applied stress or residual stress,the static tensile tests of 0.45%C steel sheet specimens are carried out on a servo hydraulic MTS810 machine.H_p(y) values are measured during the test process by an EMS-2003 metal magnetic memory diagnostic apparatus and a non-magnetic electric control displacement instrument.Residual stresses of some points on the surface of a specimen are measured by a Stress Tech X-Stress 3000 X-ray diffraction instrument.The results show that the same variation rules of H_p(y) value versus applied tensile stress are presented under the different conditions of load-on and load-off.However,the same rule does not exist between the H_p(y) value and residual stress.The variation of H_p(y) value reflects the history of applied tensile stress.