The structure of the aero-engine casing product is complex, the manufacturing precision is high, and the product processing is very difficult. In order to improve the process design efficiency and quality of aero-engine casing products, the problems that need to be solved in the 3D process design of the casing parts are analyzed, the method of 3D process design is proposed, and the technical route of the 3D process design of the casing parts is constructed. The box products have verified the feasibility of the 3D process technology and laid a solid foundation for the application and promotion of the 3D process in the aero-engine field.