CNC system is gradually developing toward flexible, component modular and re-configurable of open CNC system's structure. It's beginning a research direction in open CNC system with the software reuse and re-configurable technology. Based on the expound of concepts and characteristics of component technology, open CNC system's characteristics are analyzed based on COM and open CNC system is divided into several components. With the characteristics of binary language irrelevant, thread transparent, re-configurable and normative interface of COM technology, open CNC system's interpolate-compensation component in interpolate-compensation component achieved, interface designed and object created are researched. Better effects are achieved by connecting the interpolate-compensation component with the other CNC components. At the same time, the CNC component's real-time control problem is analyzed.