对外汉语教学的研究已经有几十年的历史，研究的广度以及涉及的范围都在不断拓展，词汇研究越来越得到人们的重视。众所周知，日语中很多汉字词，对于学习汉语的日本学习者来说，这样的母语背景必然会对他们学习汉语有所影响。汉日两种语言中同形近义词（同义词）因为意义上的相近，很容易忽略他们在用法上的区别，所以对于同形近义词（同义词）来讲，在词法方面的不同是其重点。本文将对对同形同义或近义的的汉日同形词从词法角度进行对比，从构词法和词性两个角度，考察以日语为母语的汉语学习者对于组成词的词素以及对词的结构方式的认知情况，考察他们因词性的差异而造成的使用上的不同。日本人对于同样由相同汉字组成的汉字词（在日语中没有相应的词）首先会在头脑中反映出相关的日语词汇，也就是说，日本人理解汉字的时候是和日语中有该字的词联系在一起的，一般不是求诸于单个汉字的意思。在词性方面，以日语为母语的汉语学习者对于一致的方面不容易出错，但是有差异的地方易出现偏误。与其他非汉语圈的外国人相比,教日本学生的着重点应该不一样。有效利用日语中的汉字词，在对比分析的基础上进行有针对性的教学，对于日本学生的词汇学习，甚至语法学习都有重大意义。

This thesis makes a comparative and contrastive analysis of the Homographs,Allo-graphic Synonyms And Chiasmus Words used both in Chinese and in Japanese. The thesis covers the following contents: 1 .Chinese characters used in Japanese. In this part, the author mainly introduces the definition, classification types of Chinese characters used inJapanese. 2. Allo-graphicsynonyms. In this part, the author introduces the definition and classification of allo-graphic synonyms and then makes a detailed comparative and contrastive analysis of the formation and history of them. The author finds out four causes of the formation of the alto-graphic synonyms. The first is that Japanese uses classic Chinese expressions while Chinese uses modern Chinese expressions. The second is that Japanese creates some Chinese characters. The third is that when translating foreign terminology, Chinese and Japanese use different terms. 3. Homographs used both in Chinese and in Japanese. In this part, the author divides homographs into three types: homographs with the same meaning,homographs with different meaning and homographs with similar meaning. The author also makes a detailed comparative and contrastive analysis of the meaning,formation, structure and history of the three types of homographs together with their influence on TJSL(teaching Japanese as a second language to Chinese)and on TCSL(teaching Chinese as a second language to Japanese ). In the conclusion part, the author makes some suggestions for LJSL and LCSL based on the findings of the thesis. Finally ,the author points out issues that need further studying in the future.