The definition of ‘wen’ in the preface of Shuowen Jiezi by Xushen is “creating characters is according to shape image, so the shape image is wen”. Wenshi of Zhang Taiyan studies 510 single-element characters as ‘chuwen’ in Shuowen Jiezi. He is the first scholar who proposes the concept of ‘chuwen’. Subsequently, experts in ancient writing apply the theory of ‘chuwen’ to explain the shape of ancient writing massively, representing great achievements. Based on this, the paper divides ‘chuwen’ into ‘phonetic one’ and ‘semantic one’ to study the reading method and applicative value, respectively. This paper lists 10 examples of 潮, 瓜, 訊, 要, , 範, 瓒, 金, 臨, 沐 to illustrate that ‘chuwen’ must be paid attention to in the interpretation of difficult ancient writing.