In this study, a PZTbased interface debonding defect detection approach for concretefilled steel tubular(CFST) column section is proposed and validated experimentally.The embedded piezobased functional elements(EPFEs) and piezoelectric ceramic(PZT) patches bonded on the outer surface of the steel tubular are used as the actuator and sensor respectively.Based on the amplitude of the measurement of the PZT patches under the sinusoidal excitations with different frequencies,the interface debonding defects are detected successfully by comparing the amplitude of the measurement. The defined damage index change with the different excitation frequencies is investigated.