Numerical control is a method to control the movement process of machine tool by digital signal. CNC machine tools developed in the United States in the 1950s have reached a high level in developed countries such as Europe the United States. China's CNC technology started late, but in the past 20 years, Yiming Longmen carving milling machine has made great progress, but compared with developed countries, there is still great progress. CNC technology has become an indispensable technology in modern manufacturing. It only greatly improves the production efficiency, but also greatly improves the accuracy of products. CNC machine tool is driven by NC program directly, its efficiency quality directly affect the machining efficiency of machine tool. The development of NC software programming system is also very fast, which has experienced three stages: manual programming, numerical control programming interactive graphic programming. First of all, people can only use mathematical tables desktop computers. According to the requirements of drawing data calculation, mold high-speed milling manufacturers manually program CNC program instructions according to the code, which has low programming accuracy efficiency. In order to improve the programming efficiency reduce the labor intensity of programmers, with the development of computer technology the emergence of algorithm language, people began to use electronic computers to program NC machining programs to realize automatic NC programming.