The purpose of this study is to establish a knowledge based system for education of CNC machining. The program is made based on various educational courses, teaching methodology and teaching medium etc. and has a good accessibility which can be used anywhere if computer is available. For the system, various variables according to materials, tools or shapes for machining are reviewed and analyzed. Also, the intelligent educational program is developed using Visual Basic language. It can be used to help trainees who want to refer cutting conditions for actual cutting process and also can be useful for beginner who wants to learn and to practice for CNC machining.