The simulation of NC machining system with the use of the technology of the computer graphics, both in the experimental teaching and in the production and training, has received more and more attention. In terms of the situations that the accident rate of the training of the students in the initial operation of the CNC machine tools is high, with the great damage to the machine tools and equipment, and the low efficiency of the teaching and training, we should construct the CNC experimental platform based on the simulation technology for the NC teaching and training. This paper introduces the application principles of the numerical control simulation system, the construction elements and the dynamic graphic simulation technology of the NC machining process. With the combination of the machining examples of the parts, the author elaborates the operational processes of the numerical control simulation experimental platform. Examples show that the application of the numerical control simulation technology can improve the students' ability of the NC programming, the operational abilities of the CNC machine tools, and the maintenance abilities of the CNC system. Based on the control theory, the system theory and the information technologies, the simulation technology can be used to carry out the dynamic experiments on the actual or the envisaged systems by the computer programming and the system models. The simulation in the 50s to the 60s of last century was mainly used in the aerospace, the power, the chemical industry and other industrial process control and other engineering fields. For example, using the simulation technology, we can shorten the design and development cycles of the large aircrafts. With the use of the flight simulators, we can train the pilots on the ground, which can not only save a lot of fuels and funds, but can also be not subject to the meteorological conditions and the restrictions of the sites. In recent years, with the rapid development of the science and technologies, the simulation technology has penetrated into all fields of the teaching and the researches, with the more and more extensive application in the teaching of the electronic circuits, the experiments of the mechanical principles, the experiments of the automatic control systems, and the simulation of the principles of the chemical engineering, and so on. While bringing in the enormous social benefits, at the same time, it also created the considerable economic benefits.