This paper proposed a method of measuring metal magnetic memory signal based on vibration method. A metal magnetic memory testing system was designed, including a sensor probe structure with a magnetic field shielding shell, a preprocessing module of magnetic memory signal and an orthogonal vector phase locked amplifying module. And the lower machine module was designed based on STM32F107VCT6 chip. The system is used to test the processed standard specimen. The stress concentration region of the specimen can be detected by the method of measuring the magnetic field gradient, and the relationship between the magnetic field gradient and the stress concentration factor is verified.