This article reveals some little-known historical truths about the Chinese descendant of the Thai Emperor of Thonburi，Zheng Xin，and the Thonburi dynasty，as well as the process of restoring and rebuilding tributary relations between Siam and Qing dynasty between 1767 and 1782，through annotations and annotations on the Chinese historical materials Qing History Archives and the Vietnamese historical book Da Nan Shi Lu. It fills a gap in the study of the history of Sino-Thai relations. At the same time，it cleared some historical grievances imposed on Zheng Xin，highlighting the contribution of overseas Chinese to Thailand.