For numercial control (NC) system low cost and simple operation in requiements，a NC system was developed based on human machine interface (HMI)+machine controller. Through preprogrammed common parts machining program in the machine controller, combined the manmachine interface (MMI) configured with the relevant parts of the graphics processing paramenters, it was achieved of specific parts or a particular type of specifics for NC machining. In addition, according to the actual needs in the machining parameters of different parts, with a single program, multiple parts with similar structure could be machined by the system, which solved the traditional problem of the system that G code must be setup or manually programmed before machining. So, this system has a strong operability and high practical value.