In order to obtain the influences of cutting edge radius on cutting deformation in high-speed machining Ti6Al4V, cutting temperature, equivalent stress distribution, the chip morphology and cutting deformation coefficient were analyzed in this paper. The results indicated that cutting edge changed the plastic flow of materials around tool tip and the actual tool rake angle, the tool-workpiece and tool-chip contact in cutting process which causes a greater impact on physical and mechanical performance in the given cutting conditions. When the cutting edge radius reached to 0.04mm,the cutting temperature and the equivalent stress existed mutations, which causes the mutation of chips. There was a chip thinning effect with the increase of the cutting edge radius. As the cutting edge radius increased, chip thickness and shear angle decreased, cutting deformation coefficient increased.