Abstract: In the case of offline, the magnetic memory signal of the 45 steel sample was measured by a metal magnetic memory two-dimensional scanning device. The two-dimensional components of the magnetic memory signal are subjected to differential processing to obtain the gradient of the relevant components, and the Lissajous graph of the magnetic memory signal is synthesized. By analyzing the variation characteristics between the area and the tensile load of the image, the stress concentration in the material can be quantitatively evaluated. The experimental results show that the change of the magnetic memory signal in the gap is significant when the specimen is stretched, which is favorable for the determination of the stress concentration. The correlation between the peak value of the tangential component and the tensile load is better. The size of the area is positively correlated with the tensile load, and the curve of the stress concentration of the material can be obtained by nonlinear fitting of the size of the image area.