To detect the debond defects in the foam sandwich structure material with aluminum panel， ultrasonic multiple echo-pulse method was performed. The method principle was analyzed， the artificial defect samples were made， and the automatic C-scan imaging detection was performed. The defect recognition results were analyzed by statistic calculation of the scan image gray pixel numbers. The result shows that the ultrasonic multiple echo-pulse method is effective on debond defect detection of the foam sandwich structure material with aluminum panel and provides basis for material research and evaluation.