CFRP, carbon fiber reinforced polymer, was a typical hard-to-process material that would cause serious tool wear when cut by conventional cemented carbide tools (CCTs). Therefore, the CCTs need diamond coatings. Three kinds of CCTs with different diamond coatings, namely rough-diamond, fine-diamond and compound-diamond due to depositing processes, were prepared, separately. The surface of coatings were analyzed by SEM, and the CCTs were used to cut CFRP under the same conditions to study the wear mechanism. Results show that CCTs with compound coatings have best wear resistance and longest serve life, which is almost 1.35 and 1.59 times of those of CCTs with rough-diamond coatings and fine-diamond coatings. In conclusion, CCTs coated with compound-diamond is more suitable for CFRP cutting.