Abstract: CHANG Gun (729-783) was the last prime minister during the reign of the Emperor Daizong (762-779) in Tang Dynasty (618-907), and also the most important literary consultant of Daizong (726-779). His works were widely related to the history of Daizong, and they are important in terms of historical value. More importantly, CHANG was also one of the representatives of the literary circle at that time. There is a collection of ten volumes of CHANG’s works and 60 volumes of the collection of imperial edicts related to CHANG in New History of Tang Dynasty, which is a considerable number of compositions. However, since the Northern Song Dynasty (960-1127), CHANG’s works had been lost, and there are 309 signed poems (including incomplete works or titles) in all types of literary works. Comparatively, CHANG is one whose works are most preserved in Tang Dynasty. However, there are obvious problems found in his works as did in other writers’ in Tang Dynasty, such as republication, wrong signatures, uncorrected compilation and pseudo-graph. Twenty-one of CHANG’s works are examined and distinguished one by one in order to show what the works are. On the one hand, 8 poems actually are the works by LU Lun (739-799). On the other hand, documents for CHANG Gun’s Collection are found.