In　this　study,　a　cylindrical　test　specimen　with　a　3D　through-hole　defect　was　processed,　and　the　reflected　echo　data　of　the　defect　at　different　cross-sections　were　obtained　by　an　ultrasonic　testing　detection　system.　On　this　basis,　two　data　processing　methods　were　designed　to　obtain　two　types　of　3D　reconstruction　images　of　defects,　and　the　reconstruction　effects　of　two　methods　were　compared　using　the　real　defects.　In　general,　this　study　achieved　a　relatively　accurate　3D　reconstruction　of　through-hole　defects　at　a　low　cost.　Our　methods　provided　lower　cost　than　current　state-of-the-art　approaches.