The elementary school students' brief knowledge of national defense is as follows: 1. National defense refers to military and military-related political, diplomatic, economic and cultural construction and struggle to defend national sovereignty and territorial integrity and resist foreign aggression and subversion. 2. The legal national defense education in China is held on the third Saturday of September every year. 3. People's Republic of China (PRC) National Defense Education Law was promulgated on April 28th, 2006. 4. China's national defense law stipulates that People's Republic of China (PRC)'s armed forces are composed of the China People's Liberation Army's active and reserve forces, the Chinese People's Armed Police Force and the militia. 5. The country can't stand without defense, and the people can't stand without defense. As a country and a nation, the most important things are nothing more than two major events. One is development and the other is security. National defense is the product of human social development and security needs. This is a fundamental plan related to the life and death of the country and the nation.