Hard refers to the use of super-hard tool cutting hardness greater than 50hrc hardened steel for precision cutting process. Compared with grinding, hard cutting has good processing flexibility, economy and environmental performance, using the grinding process is the best choice for hard machining hardened steel. However, hard cutting machining technology is still not fully been widely used by enterprises, the main reason is not only due to the business-to-hard cutting tool machining mechanism and the use of technology not fully understand and master, but also because of some hard cutting process is not stability factors of its application. Through a lot of general literature, on the hard cutting process of cutting force characteristics, chip formation mechanism, the role of hard-state cutting force and metal softening effect, cooling and lubrication technology and quality of machined surface were discussed, in order to promote promotion and application of hard cutting process.