Abstract: Scarf repairs are the most common method of repairing composite structures. With the development of repair technology, the problems of strength evaluation and damage detection of repaired structures need to be solved urgently. Taking the repaired laminate structure as an example, the possible types of defects and the ultrasonic characteristic signals were summarized and analyzed, which were compared and verified with repair process characteristic, to provide data accumulation for the establishment of complete ultrasonic detection criteria for such structural defects.