The samples of bearing steel, alloy cold-die steel, cold-harden cast iron were continuous machined by polycrystalline cubic boron nitride(PcBN) cutting tools dry turning. After the machining, the phases of cutting tools blade-edge were analyzed by X-ray diffraction analyzer and cutting tools blade-edge microstructure were observed by scanning electronic microscope. And then, the wear mechanism of PcBN cutting tools in turing process was studied. The result showed that the oxidation wear and felt wear were main invalidation factors using PcBN cutting tools dry turning bearing steel and alloy cold-die steel samples; chemical wear and oxidation wear were main invalidation factors using PcBN cutting tools dry turning cold-harden cast iron. In turning process, the granularity of cBN, the heated-stability and chemical characteristic of felt material have key function to cutting tools wear.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.