Abstract: Based on suppling and completing the determination principle of feeding paths in NC milling, combining with should be noted a example, feeding paths for common shape in NC milling machining was determined. It that cut in or out along the part contour lines or tangent, and in the premise of quality, can get the shortest route. Practice showed that reasonable feeding paths in milling not only makes the paths optimal, but also makes the processing time reduced by almost half, which greatly improves the production efficiency.