古文字研究的重要目的之一，在於為漢字的發展尋索並建立明確的歷史途徑，為達成這項目的，介於古文字與今文字之重要文獻──《說文》，成為研究過程中不可忽略的憑藉。因此，本文取西周晚期至秦代之間，現存刻鑄於秦青銅器上之銘文，與《說文》相較參驗，逐字比對書體，比對的內容包括「筆勢」、「筆意」及「形構」三大部分，其中「形構」又細分為「簡省」、「增繁」、「別構」及「易位」四項。經由秦文字與《說文》小筆書體的比較，探索許氏《說文》小篆書體的根源。此外，秦始皇採李斯之議行「書同文字」政策，成為文化上重要的功績之一，藉由秦金文之整理及與《說文》書體比較，可一窺秦金文異體現象，亦可檢視此一政策之成效。

One of the important purposes of the study in Ancient Chinese Characters is to seek the development of Chinese characters and set up its history clearly. To reach this project, Shuo-wen-jie-zi, the important document between the ancient Chinese characters and the contemporary characters, can’t be neglected during the study. Therefore, in this paper, I will compare the characters from West Zhou Dynasty to Qin Dynasty which had found carved on bronze with the characters in Shuo-wen-jie-zi, trying to find out the differences in “the style of writing”, “the writing conception” and “the writing structure” between them. “The writing structure” could subdivide in four items: “simplification”, “increase”, “the difference of the composition” and “the difference of the position”. After the comparison, we hope to find out the root of the characters in Shuo-wen-jie-zi. In addition, Qin Shihuang adopted the policy of “unifying the characters” from Li Si, becomes one of the important contribution in culture, therefore upon this research can not only find out the different writings in Qin’s characters but also can inspect the effect of this policy.