Based on the experiments on milling the 3Cr-1Mo-1/4Vsteel which is the main part of the large chemical equipment hydrogenation reactor with several types of different grooves milling inserts, we have experiment study on the impact disrepair. Using the Orthogonal experimental design method, we have cutting experiments on machining the high-strength steel with several types of different grooves milling inserts, and find out the difference of the impact disrepair invalidation types among them. Based on the plentiful and systemic impact disrepair experiments, we build the impact disrepair life cumulating distribution function mathematic model by the mathematics statistic method. We have contrast analysis of the impact disrepair average lives among these types of milling inserts, and the different grooves milling inserts are optimized. All these studies provide the theoretic and experimental bases for solving the cutter disrepair which is the key problem in the actual production and groove optimization.