The Tang Dynasty was a unified multi-ethnic feudal empire based on the Sui Dynasty. Most of its political, economic and military systems were inherited from the Sui Dynasty. Li Shimin, the Emperor Taizong who witnessed the storm of peasant uprising at the end of Sui Dynasty, "took the death of Sui as a warning", reformed the old system of Sui Dynasty and formulated a series of strategies to enrich Qiang Bing. In particular, the policy of governing the country by innovating politics, developing economy, strengthening national defense and military affairs, and being good neighbors at home made the social economy, culture and science develop rapidly, and successfully realized the strategic defense concept of "China is safe, and the four foreigners are for themselves", making the Tang Dynasty a top power in the world at that time. However, in the late reign of Emperor Xuanzong of Tang Dynasty, due to political corruption, the contradictions within the ruling class became increasingly acute, which led to the "Anshi Rebellion" that lasted for eight years. Since then, the Tang Dynasty has been devastated, the river has gone from bad to worse, and the unified China has fallen into a melee of five dynasties and ten countries.

As the heyday of China's feudal society, many national defense measures and characteristics of the Tang Dynasty reflected the national defense characteristics of the whole feudal society, so it has more universal significance.