在學術史上,《史通》外篇獲得的評價并不高,《四庫全書總目》及晚近學者多認為,其內容有與內篇"重出"或"抵牾"之處。追溯《史通》的學術淵源,并從理論體系的角度審視《史通》內外篇,可以發現內篇效仿了《文心雕龍》駢體專題論文的批評文體及其理論系統,外篇則在文本考證方法和述學文體兩方面繼承了《論衡》,彌補了內篇所缺乏的專書的專題研究;內篇討論"近代之史",而外篇著意于《尚書》與《春秋》經傳,亦是劉知幾為《史通》所設置的"斷限"。因而,《史通》外篇的成立,是由史學需要專書研究的性質與駢文在論述文本考證方面的不足,以及《史通》自身的學術淵源共同決定的,不能將其簡單視作劉知幾著述的初稿或者讀書札記。

The Waipian of SHITONG is rated low in academic history. The author of Catalogue of SIKUQUANSHU and following scholars consider that it repeats or contradicts the content of Neipian. Tracing back the academic origin of SHITONG, and reviewing it from the angle of theoretical system, we can find out that the articles of Neipian follow the genre and theoretical system of WENXINDIAOLONG, as well as the articles of Waipian inherit LUNHENG in terms of text research and the academic genre, which make up the special topics of books which articles of Neipian lacked. The articles of Neipian focus on the writing of "modern history", but the articles of Waipian prefer discussing SHANGSHU, CHUNQIU and ZUOZHUAN. Because of these, the independence of the articles of Waipian are determined by the need of special topics of history books and the deficiencies of parallel prose in expressing textual research, as well as the academic origin of SHITONG. They can’t be simply regarded as drafts or notes.