Titanium alloys have high strength to weight ratio, corrosion resistance, retention of strength at elevated temperatures and low thermal conductivity. In cutting of the titanium alloy, these characteristics have bad influence on tool wear. Therefore, the titanium alloy is generally machined in the milling at low cutting speed. Recently, the demand of the titanium industrial products is increasing and the high speed milling of the titanium alloy is desired. In this study, the Ti-6Al-4V alloy was machined at high cutting speed, and the tool wear progress and the cutting mechanics were experimentally investigated in order to clarify an effective tool material and cooling method for the cutting of the titanium alloy. The results obtained are as follows: In the cutting with a cemented carbide tool and coated cemented carbide tools of TiAlN, TiCN, DLC at the cutting speed 200 m/min, the wear progress of the coated tools were slower than that of the cemented carbide tool. The titanium alloy was cut in the dry and mist methods in order to avoid the thermal effect of the inserts, the wear progress in mist cutting was longer than that in dry cutting.