With the continuous development of civil aircraft design and manufacturing technology, the modular concept has been widely applied in the aircraft development process. The design of the breakdown surface is a key part of the modular design of civil aircraft. Reasonable breakdown surface design is of great significance in promoting the improvement of aircraft production efficiency, reducing costs, and facilitating maintenance. This study focuses on the design and control of modular breakdown surfaces in civil aircraft, elaborating on the trend of modular development in civil aircraft. At the same time, it studies the definition, composition and design of breakdown surfaces, introduces the concept of modular breakdown surfaces, proposes relevant requirements for modular breakdown surface design, and adopts the ICM (interface control model) method to propose the use of breakdown surface control model to effectively control modular breakdown surfaces. Compared with the original interface control file form, this model is more conducive to ensuring that information is correctly and completely implemented into the supplier’s design, research and development, and manufacturing plans, providing reference for further improving the level of modular design in civil aircraft.