In the CAM guide development process of automatic wonton machine, presents a new method of digital design and manufacturing of complex parts based on reverse engineering. The reverse engineering technology was used to realize the product development by the study of product data acquisition, the point cloud processing, surface fitting, surface parameterization modeling, digital manufacturing stages. Established the strategy of data acquisition, put forward the different method of point cloud processing, designed the scheme of surface parameterization modeling, and inspected surface quality and manufacturing process using modern means. Solved the time-consuming traditional top-down design, test difficulty and high cost, and provided a valuable experience for the application of reverse engineering technology in food machine.