National defense, that is, national defense, refers to the military activities carried out by the state to guard against and resist aggression, stop armed subversion, and defend the sovereignty, unity, territorial integrity and security of the country, as well as political, economic, scientific, technological and educational activities related to the military.

The country cannot stand defenseless, and the people cannot stand defenseless. 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.

Modern national defense takes military forces as the core, including related non-military forces; It attaches importance to the war potential of the country, especially the mobilization efficiency in wartime; It is also a competition of comprehensive strength based on economy and science and technology. The modern army is an armed group with intensive knowledge and technology, and it emphasizes quality over "sea tactics". The role of national defense in peacetime is deterrence, which requires winning without fighting; The duty of national defense in wartime is actual combat, and the goal is victory. Function:

(1) National security. (2) the premise of national independence. (3) An important condition for national prosperity and development.