Abstract: In this paper,the voltage, frequency and waveform under excitation conditions are studied, and their effects on MAE (magnetic acoustic emission) detection signal are analyzed.The experimental results show that the signal characteristics such as the amplitude of the MAE signal and the root mean square of the voltage gradually increase as the excitation voltage increases. As the excitation frequency gradually increases, the intensity of the MAE signal, the number of pulse and the sum of the pulse values all firstly increase and then decrease. When only the influence of the excitation waveform is considered, the triangular wave is not as good as the square one as the excitation source. The characteristics of the MAE signal obtained by using a square wave with a duty cycle of 50% as the excitation source are more obvious. The experimental results provide a reference for the selection of excitation condition parameters when using MAE to detect Q235 steel.