Abstract: In order to make the measurement of the depth of decarburization layer more accurate and reliable, the average method in ISO 3887:2017 and the five point average method in GB/T 224—2008 were compared and analyzed. The decarburization depth of 60Si2CrVAT steel wire rod was measured by two methods, and the measurement uncertainty was evaluated by the comprehensive evaluation method. The results show that the expanded uncertainty of five point average method was smaller than that of average method. The fluctuation of average value of five-point average method was smaller than that of average method, and the reproducibility of detection results was better than that of average method, which was more suitable for verification in case of test problems.