This paper studied characters not included in Shuowenjiezi with materials on the Qin characters excavated. The number of letters in the form of Xiaozhuan, the entries of Shuowen written in the Eastern Han Dynasty, amounted to about 9,000 letters, most of which were Qin characters, and therefore Shuowen is the most abundant and systematic material on Qin characters. As such, Shuowen is considered as authoritative literature in graphonomy research but failed to include a considerable number of Chinese characters used until the Eastern Han Dynasty. Since the 1970s, materials on Qin characters have been continuously excavated, and through these materials, 518 Qin characters that were not included in Shuowen could be collected and organized. This paper analyzed relationship between the Qin characters excavated and Xiaozhuan in Shuowen, and examined the history and transmission aspect of Qin characters not included in Shuowen by categorizing them into four periods. In addition, this study compared and analyzed the shapes of variants of the 33 Qin characters, which were not included in Shuowen, and, based on the analysis, looked into viewpoints on the selection of the standardized form of Chinese characters in Shuowen.