Abstract: In order to detect the bonded structure defects effectively, an imaging inspection system based on acoustic impedance method is constructed. The system includes three parts: acoustic signal acquisition, acoustic probe positioning, data processing and imaging. Probe positions during dynamic scanning are collected using two rotary encoders. The defect data are collected using a Bonding Quality Detector. The data processing and image drawing programs are written in C++ language. The bonded sandwich structure of aluminum alloy/epoxy resin/aluminum alloy was tested using both acoustic impedance and conventional ultrasonic C-scan imaging methods, and the test results were compared and analyzed. The results show that the acoustic impedance based imaging method can identify defects in bonded structures more effectively, and single-sided testing can meet the needs of defect detection.