The results of the experimental researches show that the high speed cutting tool is disabled in two modes of gradual wear and rapid breakage as HSC proceeds. Tool breakage occurs in low speed cutting. In process of HSC, the tool disability is the combination of flank face wear, boundary wear and cutting edge slope-plane wear. Under the action of the tool cutting movement, the ridges and furrows and burntthrough speckles and the molten metal daub phenomena come into being on the machined surface. With cutting speed increasing, it is weakened that tool wear has adverse effects on the forming of machined surface, and the workpiece surface quality is improved to a certain extent.