Interpretation to the Law of Yonghui (永徽律疏), also called Comment on Law of Tang Dynasty, represents the highest legislative achievements in the Tang Dynasty and also Chinese feudal laws. It consists of total 30 volumes, 12 chapters and 502 clauses, and is a work specialized in interpretation of the laws.

During the reign of Emperor Gaozong, the Tang Dynasty reached its peak in terms of politics, economy, and culture. In the 2^nd year of Yonghui's Reign, Emperor Gaozong ordered to promulgate Law of Yonghui, including 12 chapters and 500 clauses, based on the Law of Zhenguan. Meanwhile, considering the difference in interpreting the law clauses by central and local governments and lack of uniform standard for yearly imperial examination, Emperor Gaozong asked to give detailed interpretation to each clause of the Law of Yonghui to explain the essence, the origin of key principles, and purpose of the law, together with questions and answers prepared to solve the doubts in applying the law. They were attached to the law clauses and issued to the public in the 4^th year of Yonghui's Reign (653) under the approval of the emperor. The law clauses and their interpretations had the same legal effect. This code was then called Interpretation to the Law of Yonghui and late renamed as Comment on Law of Tang Dynasty after the Yuan Dynasty.

The Interpretation to the Law of Yonghui gave accurate and precise explanations to the main legal principles and systems, summarized the experience in making legislation and interpreting laws by ancient Chinese ruling classes based on the classics of the Confucius theory and inherited the ideas of Moral Power First and Law Second, thus developing china's feudal law to its most developed stage. With its rich contents, superb skills and unique styles, the Interpretation to the Law of Yonghui has become a representative code among the Chinese legal system and has profound influence over the legislation of the then Asian countries and subsequent feudal dynasties.