As structural materials with intelligent responsive characteristics, 4D printed mechanical metamaterials achieve dynamic regulation of mechanical properties and environmental adaptability through programmable microstructures and multi-material composite design. 4D printed mechanical metamaterials demonstrate unique advantages in terms of performance dimensions, yet their engineering application in the complex service environment of aerospace still faces numerous challenges. This paper reviews the current applications and technological advancements of 4D printed mechanical metamaterials in the aerospace domain. The article articulates the basic concepts of 4D printing and mechanical metamaterials, examines the research progress of 4D printed mechanical metamaterials and their applications in the aerospace field. The current scientific and technological challenges lie in achieving multi-scale manufacturing precision, realizing complex structural architectures, and ensuring performance stability. Looking ahead, future research should focus on the development of high-performance intelligent materials, as well as the establishment of computational simulation and optimization design methodologies, highlighting the interdisciplinary nature of 4D printed mechanical metamaterials. Such materials are expected to advance aerospace technologies toward higher efficiency, reliability, and intelligence, thereby providing strong support for technological innovation in related fields.