Abstract: This paper firstly summarizes the classification and technical characteristics of metal 3D printing process, analyzes the development trend of extreme lightweight, highly integrated and extremely high performance of the new generation of aerospace equipment such as missiles, rockets and space vehicles in detail, and clarifies the structural characteristics of the novel structure such as special-shaped complexity, macro-micro cross-scale and function-structure integration. It clarifies the technical advantages of metal 3D printing in the precision control-controlled manufacturing of new shape structures. Then, the development and engineering application status of metal 3D printing technology in aerospace field is analyzed. The current metal 3D printing technology is gradually developing from parts-level manufacturing to system-level and whole-machine level manufacturing. Developed countries abroad have realized the whole arrow, the whole star, rocket engine and other system level or whole machine level 3D printing, but the domestic still stays in the parts-level printing technology research stage, and there is still a big gap with foreign countries in terms of technical level and engineering applications. Finally, based on the development and application status of metal 3D printing technology, this paper puts forward technical direction and industrialization development suggestions from the aspects of materials, process technology, equipment and production line.