《说文解字》新附字是宋代徐铉校订《说文》时附于各部首之末的字，共402个，属于说文学研究范畴。它反映了汉字的一些造字和用字现象，体现出汉字不断孳乳的过程，对我们研究《说文》和汉字的发展有一定的意义。本文以大徐本《说文》新附字为研究对象，依据汉字发展理论和字词关系理论，对402个新附字进行穷尽性考察，较为详细地研究了这些字的来源、孳乳过程和在后世使用中的行废情况及其原因，初步探讨了汉字的分化与合并、造字多样性、形声化等理论问题。主要从两个方面展开研究：从文献学的角度，研究徐铉在校订《说文》时收录新附字的收字原因及依据。我们认为，字的使用频率和徐铉的文字观是影响收录新附字的重要因素。《字林》、原本《玉篇》等字书为徐铉收录部分新附字提供了相关依据。据此，可大致确定一些字的产生时代。从文字学本体的角度，考察这些字的产生原因、途径和造字方法。以《说文》编纂的时代为参照，根据字所记录的是否为新词，我们将新附字分为两类：一类是记录新词的字。这批字都是形声字，通过分化或形符与声符直接拼合的方式产生；一类是记录旧词的字。根据和《说文》已收字是否有关，这部分字又可分为两类：一是《说文》漏收的字，一是《说文》已收字的相关字。后者又包括《说文》已收字的异体字和分化字等情况,其中分化字有163组，异体字有26组。据此，考察了汉字演变中的形声化和新字产生的动因问题。在此基础上，我们对新附字的使用情况予以考察，初步探究新附字在使用中通行与否的原因。同时，我们还对新附字中的特殊情况——连绵字予以关注。

The 402 newly added characters of Shuowen Jiezi(Shuowen for short) are the characters attached to the end of the characters of the same radicals of Shuowen by Xu Xuan in Song Dynasty when he checked against the authoritative version. They belong to the field of Shuowen, reflect the process of Chinese characters’ multiplying and deriving, and present some phenomena about word-making and the use of characters. They are helpful to study on Shuowen and the development of Chinese characters.We focus on “the 402 newly added characters” as the research object and aim at these characters as thoroughly as possible based on the development theory and relationship theory between characters and words. We explore the derivation of the characters in detail，confirm the fact how people use and discard them and analyze the reasons comprehensively. We also inquire into the theoretical questions of characters derivation and amalgamation, word-making diversity, and the pattern of of picto-phonetic.Our study on the newly added characters is focused on two perspectives.From the point of philology, we analyze the reasons why Xu Xuan collected these 402 characters. The frequency of using these characters and Xu Xuan's view of characters are two important factors. Works on characters such as Zi Lin and the original Yu Pian provide related foundation for Xu Xuan to collect them. Thus, it can be roughly determined when some of the characters came into being. From the perspective of grammatology, we analyze the reasons for the emerging of these characters, as well as the approaches and the methods of making Chinese characters. According to the age of ShuoWen and the fact whether these characters are new words or not, the 402 characters are divided into two categories, characters recording new words and characters recording old words. The former belongs to phonograms, produced by differentiation and combination of form sign and phonetic sign. The latter can be further divided into two categories from the relationship between the newly added characters and the characters collected by Shuowen, characters that were not collected by Shuowen and characters relative to the characters collected by Shuowen. The characters relative to the characters collected by Shuowen contain 163 groups of derivation characters and 26 groups of variant Chinese characters. Accordingly, we inspect the pattern of picto-phonetic characters and new characters’ producing motivation. Furthermore, the use of “the newly added characters” of ShuoWen and the reason for general use or abolition have been studied. In addition, we also pay special attention to the characters recording two alliterated words.