In the first year of Wude (AD 6 18), Li Yuan abolished Yang Di's Daye Law, and ordered Pei Ji, Liu Wenjing and others to revise a new law according to Wendi's Kaihuang Law, which was officially promulgated in the seventh year of Wude (AD 624). Although the military moral law has some gains and losses in Huang Kai's law, it is basically the same and has not developed much. Therefore, after Li Shimin acceded to the throne, he immediately set out to improve the military ethics law. He adopted Wei Zhi's suggestion of "attaching importance to benevolence and leniency in punishment" (Volume V of Zhenguan dignitaries), and further strengthened the legislative principle of "morality is the main part and punishment is the auxiliary part" according to the Confucian thought of benevolence. In the first year of Zhenguan (AD 627), he ordered Wuji, Fang and others to practice the law again. After ten years' work, it became a generation of code, which was formally adopted in the eleventh year of Zhenguan (AD 637).
In the second year of Tang Yonghui (AD 65 1 year), Emperor Li Zhi of Gaozong led Sun Chang Wuji to revise and promulgate Yonghui Law on the basis of Zhenguan Law. Later, in view of the different understanding of the legal provisions between the central and local governments at that time, Li Zhi ordered a unified interpretation of the Yonghui Law item by item. These contents are called "regulations" and attached to the regulations. They were promulgated in the fourth year of Yonghui (AD 653), and the laws and regulations have the same legal effect. This code was called "Yonghui Law" at that time, and later it was called "Tang Law" (referred to as "Tang Law").