To achieve green machining of titanium alloy Ti-6Al-4V with water steam cooling and lubricating, a 600-800w minitype generator is developed. Compared to dry and water-based emulsion, the using of water steam improves Ti-6Al-4V machinability and prolongs the tool life about 1 time and 0.5 times. And if the same tool life was selected, it would be easy to obtain that as water steam applied the cutting speed can increase about 15% and 10%. As a result, the productivity can be increased. The excellent cooling and lubricating action of water steam could be summarized that water molecule has a small diameter and high speed, can be easily and rapidly to penetrate the capillaries and proceed adsorption in the cutting zone. The results indicate that the using of water steam has the potential to attain the green machining of titanium alloy Ti-6Al-4V.