直训的使用在《说文解字》中屡见不鲜，然而由于直训本身的局限性，人们容易将直训中的训释词意义与训释词的本义相混淆。为了帮助使用人们辨析字义，本论文从直训中训释词在训释和被训释时的意义入手，运用多种字、词典，结合前人研究，筛选出《说文解字》从一部到冊部中所有直训中训释词在训释和被训释时意义发生变化的例子。按照直训中的训释词在训释和被训释时的意义关系类型，将其分为四类——分别是引申义和本义的关系，一种引申义和另一引申义的关系，假借义和本义的关系，本义和误释字义或假借义和误释字义的关系。 此外，论文还从训释词意义变化的原因和词义演变规律两方面进行了深入探究。直训中训释词意义变化的原因主观上是因为许慎《说文》释义问题的原因，客观上主要是由词义特点和词义发展决定的。 通过对训释词和被训释词相互作用的研究，论文得出了两条词义演变的规律：一是训释词和被训释词共同作用导致词义的保留或消失；二是词义演变总是从“具象”到“抽象”。

The use of Zhixun is often seen in ShuoWenJieZi. However, due to the limitations of Zhixun itself, people have confusion of one word’s significance in Zhixun and the Benyi of this word in ShuoWenJieZi. In order to help distinguish the significances, this paper selects by category all the Zhixun, in which the word used to explain another one shows different meanings when it is explained, out from "chapter 一" to "chapter 冊"in ShuoWenJieZi. According to the word meaning types which is used to explain others in Zhixun, all these Zhixun will be divided into four categories including Yinshenyi and its Benyi, one kind of Yinshenyi and another kind of Yinshenyi, Jiajieyi and Benyi,and Benyi or Jiajieyi and Wushiziyi. In addition, the reason why the significance changes in Zhixun and the laws of the evolution of the word meaning explored in depth in this paper. The reason why the words which is used to explain others in Zhixun changes their significances are summed up in two points as follows: subjectively because of the way that Xushen used to explain words in ShuoWenJieZi; objectively because of the characteristics and the development of significance of a word. The laws of the evolution of the word’s significance are summed in two rules. The first is the interactions of words which is used to explain and which is explained in Zhixun lead to the retention and loss of word meaning. The second is evolution of the word significance changes from "concrete" to "abstract".