Abstract: The new structure of π shaped steel-concrete composite beam has been under fatigue load for a long time during service, and it is necessary to monitor the fatigue damage of its interface. An active sensing wave monitoring method and monitoring test based on piezoelectric ceramics is proposed. The method is to judge the damage state of the interface of π shaped steel-concrete composite beam by comparing the time domain signal and wavelet packet energy changes received by each sensor under the health state and different fatigue loading times. The results show that, increasing the fatigue times of cyclic load, the time domain signal amplitude and wavelet packet energy of each sensor response signal show an overall downward trend. Both time domain signal analysis and wavelet packet energy analysis can reflect the damage degree of specimen, and the wavelet packet energy analysis method has higher sensitivity, the π shaped steel-concrete composite beam interface has good fatigue bonding performance, the active sensing monitoring method based on piezoelectric ceramics is the feasible.