High-speed machining has received important interest because it leads to increase of productivity and a better workpieces surface quality. Holwever, at high cutting speeds, the tool wear increases dramatically due to the high temperature at the tool-workpiece interface. Tool wear impairs the surface finish and hence the tool life is reduced. That is why an important objective of metal cutting research has been the assessment of tool wear patterns and mechanisems. In this paper, the wear performances of PCBN tool, ceramic tool, coated carbide tool and fine-grainde carbide tool in high-speed face milling are presentde when cutting cast iron, 45 temperde carbon steel and45 hardende carbonsteel. The tool wear patterns were examinde through a toolmaker's microscope. The research results show that the tool wear types differed in various matching of materials betweenthe cutting tool and the workpiece. The dominant wear pattrens observed were rake face wear, flank wear, chiping, fracture and breakage. The main wear mechanisms were mechanical friction, adhesion,diffusion and chemical wear promoted by cutting fores and high cutting temperature. Hence, the important considerations of high-speed cutting tool materials are high heat-reistance and wear-resistance, and chemical stability as well as resistance to the failure of coating. The research results will be of great benefit in the design and Science B.V. All rights reservde.