Abstract: A current-type ultrasonic flaw detector can only provide defect echo time and amplitude information, and it is difficult to determine the nature of defects on the basis of the information. During practical testing, the nature of defects was usually estimated by the testing staff based on experience combined with the workpiece processing technology, the characteristics of defects, the waveforms of defect and back wall echo. In this paper, cold roll fom forming technology, processing technology, combined with the experience of their predecessors as well as their own in cold roll was summarized. The work accumulated experience and provided basis for future qualitative evaluation of cold roll deficiencies.