Titanium alloy is widely used in typical aerospace structural parts because of its excellent mechanical properties and corrosion resistance. However, the serious problem of tool wear in the machining process of titanium alloy often leads to the decline of machining quality. In this article, scCO2 MQL cutting experiment and dry cutting experiment of TC11 are carried out. The machined surface morphology, plastic deformation, residual stress and tool wear were analyzed. The results show that scCO2 MQL can effectively reduce the surface defects on the machined surface. The increase of cutting edge structure and blunt radius of the composite increases the plastic deformation degree of the material, as well as the residual stress and work hardening degree. The scCO2 MQL can effectively improve the cutting contact area and reduce tool joint wear.