High-speed milling of titanium alloys is widely used in aerospace industries for its high efficiency and good quality of product. The paper empirically studies surface roughness, topography and microhardness variations in high speed milling of Ti6Al4V alloy. The experiments were conducted under minimum quantity lubrication environment. Carbide end mill tool with TiAlN coating and 6 millimeter diameter was used. Full factorial method was used to design of experiments and analyze the effect of machining parameters including cutting speed and feed rate on surface roughness, topography and microhardness. The other cutting parameters i.e. axial depth of cut and radial depth of cut were constant. The results showed that a high quality surface with roughness of 0.2 µm can be obtained by using high speed machining method. Also, microhardness variations versus cutting speed has two-fold nature. It indicates that firstly, by increasing cutting speed up to 375 m/min, microhardness increases and after that, it declines remarkably. In addition, by increasing feed rate, surface microhardness rises and the maximum microhardness was obtained in cutting speed of 375 m/min and feed rate of 0.08 mm/tooth, which showed 57% increase in regard with hardness of the base material. The Images of surface topography showed that increasing of the cutting speed has a significant effect on reduction of surface tears and smears.