In view of the parts with concave convex contour and the characteristics of SINUMERIK 802S/C, the traditional method of copying cutting cycle was improved, so as to increase the machining efficiency of CNC turning. LCYC96 was designed, which was used to rough machining the concave contour with high efficiency copying method. The part was processed, combining with the cycle of cutting blank LCYC95. It is proved that the algorithm is correct and the cutting efficiency is greatly improved by taking a practical example.