Defects of the final surfaces of cemented carbide inserts by means of conventional grinding method include grinding burn, crack, and thermal deformation, causing low cutting efficiency. To address the problems of the conventional way in grinding the insert surfaces, the chemical mechanical polishing (CMP) process is adopted in finish machining rake faces. First, the CMP process parameters are optimized with orthogonal experiments and Taguchi’s method, and the cemented carbide insert surfaces are made with 14.399 nm Ra of its rake face. Second, the inserts made with the conventional grinding and the CMP methods are used to lathe 1Cr18Ni9Ti austenitic stainless steel. Under the same cutting conditions, the cutting forces of the polished insert is less than those of the grinding insert, the cutting time of the polished insert is longer than that of the grinding insert, and the average life of the polished insert is 32.3% longer than that of the grinding insert. Finally, the scanning electron microscopy (SEM) and the energy dispersive spectroscopy (EDS) analysis have shown that the polished insert rake face has less adhesive wear , abrasive wear, and minor oxidation wear compared to the wear of the grinding insert rake face. This study demonstrates that the CMP is a potential way of processing the insert surfaces in the tooling industry.