Abstract: During the operation of a nuclear power plant, the heat transfer tubes of the steam generator will suffer from wear defects due to the wear of the support plates. However, traditional eddy current testing methods have limitations in the quantitative and qualitative analysis of wear defects. In order to solve this problem, based on the field practical experience and the results of experimental demonstration, this paper proposed a quantitative evaluation method for the wear depth of heat transfer tubes of steam generators. Through in-depth quantitative optimization research for different types of wear defects, the accuracy of Bobbin probes was greatly improved.