中國古代典籍異文繁多，古人訓釋典籍，理當參詳眾本異文，考定字句意義。在校勘學研究方面，前人所論古人校書方法，亦有謂其廣集異本，進行比對校勘，把注家引用異文當作專為校勘之手段。至於訓詁學及異文研究的討論方面，前賢學者亦以為古人注書標示異文，僅為展示他本差異，校勘異同。即使論及異文，亦只局限於討論同一種書的不同版本，或今古文之別，並認為直至清人注書校書，方通過異文比對，探求古書字詞真義。本論文集中討論韋昭《國語解》，輯錄書中有關異文，囊括古今文字異文、互見文獻、引書異文、類書異文等，以之比對該書注文，查考當中有關聯者，根據韋昭《國語解》的異文選材，查探其注史方法。

It is generally believed that annotators before the Qing dynasty provided textual variances of ancient texts simply for the purpose of collation. This thesis proposes that textual variances actually serve as a type of commentaries on language and content from the Han through the Tang dynasties, and it examines the various examples of such usage.The texts covered by this study concentrate on Wei Zhao's 韋昭（ca. 204–273）Guoyu jie 國語解. It evaluates Wei Zhao’s method in commentating Guoyu and comparing it with Du Yu's 杜預（ca. 222–285） annotation to the Zuo zhuan 左 傳.