This is a study on the discrepancies between Liu Yuxi’s 劉禹錫 (772-842) biographies contained in the Jiu Tangshu 舊唐書 (Old Tang History) and the Xin Tangshu 新唐書 (New Tang History). For this study, Liu's biographies in the two Tang histories are cho sen as primary sources for Liu's official life. Then, I try to find out the discrepancies bet ween the two biographies. This paper contains an annotated translation of Liu's biograph y in the Jiu Tangshu and discrepancies between his two biographies in the Tang historie s. In addition, other pertinent materials including Liu’s autobiography Zi Liuzi zizhuan 子 劉子自傳 are also employed. In the translation, the biography is divided into twenty sectio ns by my own determination in order to effectively compare with Liu's biography in the Xin Tangshu.