蝶形图是交流电磁场检测（alternating current field measurement, ACFM）中判定缺陷存在的一种重要方法。为研究常规裂纹蝶形图与裂纹剖面的映射关系，首先利用COMSOL Multiphysics实现不同尺寸裂纹的数值模拟，并建立了长度和深度特征量的重构方程。其次通过对比，分析了蝶形图与裂纹剖面的内在关系，进一步结合图像处理法和常规线性拟合方法分别建立了两者的映射关系方程。最后，对Q235钢不同尺寸的槽状裂纹进行了检测试验。试验结果表明：基于长度和深度的裂纹剖面误差分别为5.46%和6.02%。该研究实现了蝶形图的再利用，为缺陷的风险评估方法提供了重要的参考。

Butterfly diagram is an essential method for determine the presence of defects in alternating current field measurement. To study the mapping relationship between conventional crack butterfly diagrams and crack profiles, COMSOL Multiphysics was first used to numerically simulate cracks of different sizes, and reconstruction equations for length and depth feature quantities were established. Secondly, through comparative analysis, the corresponding relationship between the characteristic signal and the butterfly diagram was explored, and a mapping equation between the two was further established by combining image processing methods and conventional linear fitting methods. Finally, detection tests were conducted on groove shaped cracks of different sizes of Q235 steel. The experimental results show that the crack profile errors based on length and depth are 5.46% and 6.02%, respectively. The study achieved the reuse of butterfly diagrams, providing important references for defect risk assessment methods.