National defense education and coastal defense knowledge have different meanings. National defense education is a social activity to defend national sovereignty, territorial integrity and security, resist the construction and struggle of foreign aggression and subversive threats, and impart ideas, knowledge and skills related to national defense to the whole people. Coastal defense knowledge refers to the defense of coastal coasts and islands and reefs. In China, there are coastlines of Bohai Sea, East China Sea and South China Sea, as well as large and small offshore islands, such as Hainan Island, Taiwan Province Island, Diaoyu Island and Huangyan Reef. The important content of national defense construction includes all kinds of social activities to enhance the national defense thought, knowledge, skills and physical quality of the whole people and help form and improve the national defense concept and ability.