Benzoxazine resin as a new type of thermosetting resin has been widely used in electronic packaging materials， aerospace industry， rail transportation and other fields. In this paper， preparation routes and synthesis methods of benzoxazine monomer are summarized， and the ring-opening polymerization mechanism of benzoxazine monomer is summarized. The modification progress of benzoxazine resin in heat resistance， toughness and other aspects are emphatically described， and then the application progress of benzoxazine resin in the molding process of composite materials such as prepreg and RTM is introduced. Finally， the development trend of benzoxazine resin and its composites are prospected.