Abstract: To provide a virtual manufacturing environment and verify machining process, research on the simulation method for machining process on computer is conducted in the paper. A simulation system for machining process is developed based on OpenGL by Visual C++6.0. In the system, the simulation of 17 kinds of often used machining, including turning, milling, planning, grinding, etc., is realized. The animation of cutting tools movement and the material removing of part can be controlled by some process parameters, such as cutting speed and cutting path. The time and cost of machining can be computed automatically and optimized. The system is user-friendly and ease-to-use and can run rightly and effectively.