Abstract: Aiming at the problem that the characteristic of MAE signal is affected by excitation intensity and frequency, a magneto acoustic emission detector with variable excitation amplitude and the ability to measure hysteresis loop is needed. The influence of the size of the exciter and the number of excitation coil turns on the excitation ability is studied, and the optimal excitation yoke size and number of turns are determined. Finally, the overall performance of the magneto acoustic emission detection device is evaluated. It is found that when the 8# yoke is wound around the coil 600 turns, the magnetic flux potential in the design of the exciter is satisfied. At this time, the magneto-acoustic emission detection device has better excitation performance and has a practical and broad application prospect.