It is critical to control chip forming, regular curling and breaking in turning. One method most commonly used is to make chips curl and break with chip-breaking grooves. Chip-breaking groove designing is complex and affected by several factors. Cellular automata is especially used to solve problems in complicated situation, hence this paper adopts cellular automata to design curves of the grooves. After blending the curves through Pro/Engineer into part, an insert with three-dimensional complex groove was developed with EDM. The results of cutting experiment showe a great performance of the grooved insert in turning, reaching the expected goal, and feasibility to design a three-dimensional complex groove insert with cellular automata as well.