This work aims to improve the cutting efficiency of coated twist drill for machining austenitic stainless steel. According to different process routes of polishing before coated and polishing before and after coated, the advanced polishing technology of tool substrate and coating was adopted to prepare carbide twist drill. Then, two kinds of the polished and coated twist drills and the coated twist drill which untreated by polishing process were selected to drill austenitic stainless steel, and the influence of the polishing technology before and after coated on the durability, wear morphology and wear mechanism of coated carbide twist drill were analyzed. After the initial surface of the coated carbide twist drill was polished, the average surface roughness of the flute rake face decreased from 10.77 μm to 5.09 μm, and the reduction range reached 52.7%, and the surface quality of the coating was significantly improved. When given the same cutting condition, the durability of twist drill was polished before and after coated and twist drill was polished before coated was 150% and 106.1% higher than that of unpolished twist drill respectively, and the durability of twist drill was polished before and after coated was 21.3% higher than that of twist drill was polished before coated. The failure causes of unpolished coated twist drill were crater wear, tip chipping and chip adhesion. The failure causes of twist drill was polished before coated were crater wear, notch wear around the cutting edge and coating peeling off. The failure causes of twist drill was polished before and after coated were micro chipping, coating peeling off and chip adhesion, and the damage degree of it was the least of all. The polishing technology of tool substrate and coating surface of the common coated twist drill has remarkable advantages in reducing the damage degree of machining austenitic stainless steel and prolonging its cutting life, which can greatly improve the comprehensive performance of the tool.