The microstructure and mechanical properties of a new- type of cermets cutter ( tool A ) with nano- TiN modification and its cutting properties in cutting gray cast iron are investigated.SEM and TEM observations of the microstructure of the above material reveal that nano- TiN modified cermets possess a finer microstructure than conventional cermets .In the cutting tests, for comparison, cemented carbide cutter ( YG8 , tool B) was also utilized.The cutting results show that the cutting properties of tool A are superior to those of tool B.It is also found that the predominant failure mode of tool A is normal wear and micro-spalling under lower cutting quantities, and that chipping occurs under higher cutting quantities.SEM analysis reveals that cohesion, oxidation and diffusion wear become very apparent at a higher cutting speed.On the contrary, grain wear also exists but is not apparent.