In order to solve the problem of large error in the measurement value of circumferential edge wear, an evaluation method of the circumferential edge wear of milling cutter based on the reconstruction of wear zone was proposed. Based on the image of the wear zone obtained by video microscope, a 3D reconstruction and surface expansion mapping model were established. Then the 3D reconstruction of the wear zone of the flank wear zone of circumferential edge was completed, and the approximate plane expansion of the spiral surface of the perimeter edge was completed. The geometric transformation was used to complete the representation of the first and second flank wear zones in their respective planes and their coplanar representation so as to obtain the equivalent plane wear zone. Through the analysis of equivalent plane wear zone, the wear width and wear area of the flank were obtained, and the accurate evaluation of the circumferential edge wear was further finished. The empirical study on the wear of the four-edge milling cutter (the cutting time is 57 min) found that the average wear width and area obtained by the reconstruction method were 0.16 mm and 0.067 mm² higher than those obtained by the direct method on average, and the increase rates were 17% and 14.9%. The results show the feasibility and accuracy of the reconstruction method.