Abstract: The Shuowen Jiezi Xizhuan is the earliest explanatory book about Shuowen,which had been written by XU kai of the NanTang Dynasty.After Shuowen Jiezi was revised by XU Xuan,its circulation decreased,and it was not published in Yuan and Ming Dynasty.In Qing Dynasty,there were various versions again but the quality was not ensured.This thesis makes an investigation on the source of the book and introduces the current important version.