Chu Shaosun, important as a man who made an unofficial attempt after Yang Yun to supplement the content of the Shiji, played a leading role in promoting both the practice of making editorial additions to the Shiji and the early dissemination of the book. Problems concerning Chu’s additions to the Shiji involve many aspects of the Shiji literature and have been the subject of much controversy. Efforts to solve these problems have largely been limited to identifying chapters or parts of chapters in the book as Chu’s additions. Scholars have tended to neglect such basic questions as the maintenance and dissemination of the Shiji in the Western Han Dynasty, the text on which Chu based his additions and its source, the date when he wrote his additions, and the date when his new material was incorporated into the book. Thus despite the great quantity of textual criticism produced over the years, the quality of this criticism seldom goes beyond mere conjecture. This article inquires into these basic questions so as to provide a more objective basis for hypotheses about Chu's work. It argues for three main conclusions: (1) Chu Shaosun did not see the reserve copy kept in the imperial library, nor did he see the duplicate kept in Yang’s home. What he saw were fragmentary chapters circulating among the public that had been reproduced from Yang's duplicate. (2) Chu was appointed Court Academician during the Reign of Ganlu of Emperor Xuan, and his editorial additions to the Shiji were made during the reigns of Emperor Xuan and Emperor Yuan. (3) His additions were incorporated into the book at the end of the Eastern Han Dynasty.