As a key technology in modern engineering field, the damage repair of composite materials in service is very important to ensure the long-term reliability and economy of the materials. The repair technology of composite materials is directly concerned with the performance recovery after the damage of materials or structures, and the repairability is the problem of how to reduce the difficulty of repair in the design and manufacturing stage of materials and structures. In this paper, the characteristics, technical development, shortcomings and problems encountered in engineering applications of traditional processes such as patching repair, digging repair, glue injection repair and mechanical connection repair are reviewed. The principle and progress of external and intrinsic self-healing composite materials and the technological development of deadhesive adhesives for replacement repair are also summarized from the perspective of composite materials and their structural repairability. Finally, the main technical difficulties that need to be overcome in the study of repair technology and repairability of composite materials are summarized.