Li Longji was born in August of the first year of Emperor Taizong (685) in Luoyang, the eastern capital. He is born wise and decisive, knows the rhythm and has a gorgeous appearance. At the beginning, he was named King Chu, and later he was named King Linzi. He served as Wei Guo, Shao Qing and Luzhou. In the first year of Tang Long (7 10), Li Longji and Princess Taiping jointly launched "Tang Long" to destroy Wei Hou Group. In the first year of his birth (7 12), Li Dan Zen was located in Li Longji, and Li Longji ascended the throne in Chang 'an Taiji Palace.
In the early days of the reign of Emperor Xuanzong of Tang Dynasty, he made great achievements in politics. He was diligent in political affairs and took various measures to consolidate and develop the Tang regime. Emperor Xuanzong of the Tang Dynasty paid attention to bringing order out of chaos, appointed Yao Chong, Song _ and other sages, made great efforts to govern, and created the prosperous time of the Tang Dynasty-Kaiyuan. However, in the later period of his rule, he gradually ignored state affairs and supported treacherous court officials Li and Yang. Yang Guifei, who was a great lover, combined with policy mistakes, tried to stabilize the frontier of the Tang Dynasty by reusing An Lushan and other ethnic groups beyond the Great Wall, which led to the eight-year Anshi Rebellion and laid the foundation for the decline of the Tang Dynasty. In the fifteenth year of Tianbao (756), Prince Hengli ascended the throne.
In the first year of Baoying (762), he died in the Shenlong Hall in Chang 'an at the age of 78, and was buried in Jinsu Mountain, named Tailing. Temple name Xuanzong, and because of its posthumous title as the most holy, Daming, filial emperor, Emperor Kangxi's name was taboo in the Qing Dynasty, often called Tang, and was honored as the Kaiyuan emperor.