Since Xu Xuan revised Shuowen and supplemented it with “Newly Appended Characters”, the study on it has become an important part of the Shuowen studies. There are three main viewpoints developed in later generations on how to understand “Newly Appended Characters”. First, totally negative one, such as Qian Daxin. The second is that “Newly Appended Characters” is based on the orthographic Characters since the Tang Dynasty, such as Wang Mingsheng. Last, it is believed that it is inherent in Shuowen before the Tang Dynasty, such as Yan Kejun. In this paper, a textual research of 52 newly appended characters has been taken by both using the data of Shuowen cited in Huilin Yinyi慧琳音義 and combining it with the previous literature. It is speculated that one of the 402 newly appended characters of Xu Xuan’s gain is originally owned by the ancient version of Shuowen.