Li Zhi is the ninth son of Taizong, his mother is Zhangsunhuangzhou, and he was granted the title of King of Jin in 631. In 643, two elder brothers, Li Chengqian and Li Tai, failed to compete for the throne. With the support of his uncle Zhangsun Wuji, he was established as Crown Prince. He ascended the throne in 649 and changed the Yuan Dynasty to Yonghui the following year. He relied heavily on the old ministers of Zhenguan, and his politics were clear and bright. It was known as the "Government of Yonghui" in history. The "Tang Lv Shu Yi" was promulgated at this time.
In 655, despite the opposition of Zhangsun Wuji, Chu Suiliang and other elders, he deposed the king and queen and installed Wu Zhaoyi as his queen. After that, the elder groups were eliminated one by one. After Xianqing, he suffered from rheumatism and often asked Empress Wu to handle memorials. The two of them were known as the "Two Saints". Externally, Su Dingfang destroyed the Western Turks, and the Tang army successively destroyed Baekje and Goguryeo, and established Anxi, Andong and other protective prefectures. The Tang dynasty territory reached its peak.
In the later period of Gaozong, Tubo rose, the Tang army suffered a disastrous defeat in Dafeichuan, and the four towns of Anxi fell for a time. Crown Prince Li Hong died young, and the successor Li Xian was deposed. Empress Wu became increasingly powerful. In December 683, he died of illness in Luoyang. He ordered Crown Prince Li Xian to ascend the throne. Any major military and state affairs that could not be resolved would be decided by the Queen of Heaven. He was buried in Qianling Mausoleum the following year.
Gaozong is often regarded as a cowardly king, but during his thirty-four years in power, Tang Dynasty successively destroyed Western Turks, Baekje, and Goguryeo, and his territory reached its peak. The promulgation of "Tang Laws and Regulations" and the reform of imperial examinations also had far-reaching influence. He was generous and sick, and relied heavily on Empress Wu to assist in government affairs. Although he once tried to abolish the empress, he was ultimately unable to restrict his power, which paved the way for the future of Wu Zhou and Tang Dynasty.