Abstract: Continuous cutting tool lifespan testing and intermittent cutting damage lifespan test were carried out for ultrafine-grained WC-Co cemented carbide tool and general cemented carbide tool with different cobalt content under the condition of turning GH2132 super alloy at high speed. Based on the relationship between tool lifespan and cutting speed, the T-v empirical formulas were set up by the method of least squares. The wear and breakage figuration of the tool edges, the rake and flank faces were observed by ZEISS optical stereo microscope and microphotography system. The experimental results indicate that the main wear and breakage mechanisms of WC-Co cemented carbide tool is adhesive wear; the wear resistance of ultrafine-grained WC-Co cemented carbide tool is much higher than that of conventional cemented carbide; appropriately increasing Co content is beneficial to improve the wear and breakage resistance of ultrafine-grained WC-Co cemented carbide.