Abstract: Some typical kinds of coated carbide inserts made in China were systemar-tically tested and studied in cutting high-strenghth alloy steels and carbon steel. It has been made clear that coated carbide inserts have longer tool lives than uncoated inserts, especially the inserts with TiC or multi-layer coat-ings. The T-v relations of coated carbide inserts were also studied, and the "peak"characteristic of the T-v relation was made out. Based on the tests and atudies, some explanations and analyses on the mechanism of the wear resistance of coated carbide inserts are provided in this paper.lt is hoped that this psper would help the further application of and provide more information about coated carbide inserts