Abstract: Titanium alloys have been widely used in aerospace for their excellent heat-resistant, erosive-resistant and especially high strength-to-weight ratio. Grinding burn is apt to occur in the grinding process of titanium alloys. The grinding burn mechanism of titanium alloys was studied on the base of systematical analysis of variable characteristics of the grinding force, grinding temperature, surface roughness and topography of ground surface, hardness distribution of surface layer, as well as morphology of surface layer from a metallographic point of view. Some conclusions were given as follows. The grinding burn occurs at the temperature over 600℃. The surface topography deteriorates gradually with elevating grinding temperature. When severe burn appears, some microcracks perpendicular to the grinding direction on the surface of the test-piece are found. With the onset of grinding burn, α phase particles become coarsening, which deteriorate the mechanical properties of titanium alloys obviously. The results provide a theoretical and experimental basis for technical optimization in the grinding of titanium alloys with high efficiency and high quality.