In this paper, the latest trends and core significance of programming and optimal design of composite machining as a cutting-edge field are explored in detail. At the beginning, we set up a research stage, described the academic background of today's compound machining programming and optimization design, and highlighted its universal adoption in industrial production and its decisive role in improving the excellent performance of products. Our goal is clear, aiming at deconstructing key technologies and looking forward to their potential wide application scenarios. In the main part, we not only explain the basic principles and innovative technologies in this field, but also analyze the efficiency improvement of compound machining programming in real production environment through examples, and show how it reshapes the economic benefits of manufacturing industry. In addition, through a series of successful optimization design cases, we extract the key success factors and lessons, so as to show its revolutionary power in the manufacturing process.