The Ti-6Al-4V alloy was hydrogenated at 800°C by thermohydrogen treatment technology. To research the influence of hydrogen contents on cutting force and cutting temperature, the turning experiments were carried out by applying uncoated WC-Co cemented carbide tool. The results show that the most decrease amplitude of main cutting force is about 11%, and the cutting temperature reduces most by 85°C in the given conditions. Moreover, the change law of cutting force and cutting temperature is both as follows: firstly decreases and then increases with the increase of hydrogen content, and the optimum hydrogen content is 0.26%. It is considered that reasons of the change law are attributed to comprehensive effect of hydrogen contents on microstructure, flow stress, impact ductility, elastic modulus, microhardness, thermoconductivity and friction coefficient of the Ti-6Al-4V alloy.