Abstract: RTCP function is the keyfunction of the 5-axis machine. RTCP is a necessary function in the development of high-grade CNC system. The RTCP function of high-grade CNC system can not only be the basic RTCP function, but also need to support multi structure machine tools, tilt rotation axis, 3 + 2 bevel machining, vector interpolation and other advanced interpolation functions. This RTCP function module is relatively complete. This paper summarizes all aspects of the RTCP function development, which has a certain guiding significance for the RTCP function development of CNC system.