The key technology of the cutter that cutting hardened steel was researched by high speed milling machining method. At first ,three cutting elements of high speed milling machining was narratived, and we can obtain the principle of selection of parameters of cutting velocity, feed per tooth, longitudinal cutting depth and cutting width of axial, etc. With HSM ,we discussed the performance and selection points of tool material of coated cemented carbide, ceramic, cubic boron nitride , synthetic diamond and so on, and obtained the effect of the main tool geometry for the cutting process in HSM. The second, it analysised type and reason of damage of high speed cutting tools, and introduced three detection methods of tools. Finally, it was summarized and concluded.