Abstract: With the development of automation and CAD/CAM technology, teaching programming can't meet the needs of the robotic machining technologies. Auto-programming on robots can be realized by G-code, which can be easily acquired from almost any kind of CAD/CAM software. This paper clarifies the feasibility of the transformation from G-codes to Job instructions of robot systems, analyzes in detail the transforming algorithms between G-codes and Job instructions considering the differences between NC machine coordinates and robot coordinates, and discusses track simulation, error-testing and dynamic optimization from the view of programming.