CNC system is the core component of machine tools. CNC system mainly controls the movement of machine tools. CNC system can accurately control the position, angle, speed and other mechanical and switching quantities of machine tools. Imported CNC systems will be equipped on domestic medium and high-grade machine tools. Domestic CNC systems will generally be seen on low and medium-grade machines. Domestic CNC systems cannot be equipped on some high-grade machines. Because domestic CNC systems are not good at performance, stability and reliability, so general machine tool manufacturers will not equip domestic CNC systems with high-grade machines. On the other hand, it is a good choice to configure imported CNC system on high-end machines. The performance, stability and reliability of imported CNC system are very good. There are many CNC systems imported in China, such as Germany Siemens, Japan Fanuc and Mitsubishi, Taiwan Baoyuan and New Generation, which are well-known CNC systems in China. At present, the FANUC CNC system in Japan is the most popular CNC system in China, followed by Siemens in Germany and Mitsubishi in Japan. These imported CNC systems take advantage of their advanced data and the superiority of CNC system's performance to occupy the domestic CNC market rapidly, so the domestic CNC system has little market share in the domestic market. The characteristics of imported CNC system are that there are many brands of imported CNC system, and their characteristics are almost the same. It seems too slow to talk about the characteristics one by one, besides the small edition. Take Fanuc CNC system of Japan, which is widely used in domestic machine tools, as an example. Fanuc CNC system has the characteristics of high quality, high performance, full function, use and various machine tools and machines. Fanuc CNC system is mainly embodied in the following aspects: 1. Its structure is simple, easy to disassemble and assemble, and each control board is highly integrated, so its reliability is greatly improved, and it is convenient for maintenance and replacement. 2. The temperature and relative humidity of Fanuc NC system are 0-45 and 75% respectively, which shows that FANUC NC system has strong adaptability to environment. 3. The software of Fanuc NC system is complete, which can meet the requirements of general machine tools.