Abstract: Tianzhang Royal Institute which was established in the period of Song Zhenzong, was of the utmost importance among various Royal Institutes that stored the collected works of emperors, royal collections, and archives in the imperial palace of Song Dynasty. With painstaking management on the foundation of the huge collections of Tianzhang Royal Institute,during the period of Song Renzong,who set up some official positions such as the Clients, Serving Study, and held a series of political activities like the talk with emperors, holding court,the Classic Lecture. It became an essential part for the discussion of political affairs and the audience with the emperor in the inner court. At the beginning of the Southern Song Dynasty,Tianzhang Royal Institute was used to store the portraits of emperors and political archives after its reconstruction, due to the adjustment of the interior structure and functions in the inner court of the Southern Song Dynasty. New ceremonies were also established as a way of showing respect. Meanwhile,the official position of the Clients turned to be nominal in late Northern Song Dynasty; as a result, the official position of Tianzhang Royal Institute, which had been a kind of civil position holding real power, was merely an official title at the time. The establishment of Tianzhang Royal Institute and the evolution of its official positions and titles on the one hand indicate its special status among all Royal Institutes in Song Dynasty; on the other hand show the reform of the Royal Institutes in the inner court and the transformation of the Clients’ administrative function during Song Dynasty.

Key words: Tianzhang Royal Institute, the imperial conference, the portraits of emperors, political function