Abstract: Aiming at the abnormal signal during lamb wave testing of inconel 600 cold rolling strip, low-frequency eddy-current detection and ultrasonic thickness measurement using delay block were used together, the origin of reflection which had brought the abnormal signal was accurately oriented, and the character of flaw at the origin of reflection was analysed and judged. Finally the accurate cutting sample location found by the two above-mentioned techniques was analysed by metallography.