The most famous mention of the Tang Dynasty in history is not the prosperity of Buddhism, but the struggle between the Tang Dynasty and Buddhism. Fu Yi in the early Tang Dynasty and Han Yu in the late Tang Dynasty both sharply criticized Buddhism. But its prosperity is also beyond doubt. Historical reasons began in the Sui Dynasty. Wendi was born in a Buddhist temple, grew up in the hands of a nun and was greatly influenced by Buddhism. After the Northern Zhou Emperor banned Buddhism, Wendi strongly advocated Buddhism. Sui and Tang dynasties were closely related, so Buddhism continued to flourish after the change of ownership. Although Taoism was highly respected in the early Tang Dynasty, Buddhism was not excluded. The key figure is Wu Zetian. After becoming a female emperor, she strongly advocated Buddhism, and the power of Buddhism reached its peak at this time. Xuanzong restricted Buddhism in the Tang Dynasty, and Tang Suzong and Tang Daizong praised Buddhism in the late Tang Dynasty, which led to a considerable temple economy, while monks intervened in political affairs. Later, Emperor Xuanzong of the Tang Dynasty and Tang Yizong worshipped Buddha. In addition, there were few taboos in the Tang Dynasty, and the scientific and cultural policies were enlightened. Generally speaking, most of the rulers in the Tang Dynasty advocated Buddhism, which is the fundamental historical reason for the prosperity of Buddhism in the Tang Dynasty. Because religion is closely related to politics, religion can flourish only with the support of the ruling class.