Out of autoclave process (OoA) technology is an effective way to achieve low cost manufacturing of structural composites and one of the hotspots in the field of composite materials research.The research frontiers and applications of OoA composites in aerospace field at domestic and overseas are introduced and the defect control methods in OoA forming process are summarized from two aspects of material system and forming process.In the process of OoA preprepreg forming,the void fraction of composites can be effectively reduced by minimizing the volatile content in the resin, fine controlling the reaction and rheological properties of the resin,controlling the infiltration degree of fibers and resins in the prepreg and optimizing the forming process.