Gogeum Seongnim (Gujin Shilin) written by Lee Euibong (Li Yifeng), a scholar of the Joseon Dynasty, is representative of Chinese dictionary in the Joseon period. Its collected Chinese characters have large vocabulary, a long time span, and a wide range of contents, which are extremely valuable for the study of Chinese character communication outside China. However, the book is vast in traditional Chinese characters. And the creation of this book was after twists and turns. There are still many errors in the Chinese characters included in the book. Therefore, it is necessary to correct the wrong Chinese characters. In addition, the corruption of ancient Korean writing is not uncommon. This means that it is necessary to collate Chinese dictionaries and correct the wrong Chinese characters at that time, which is the basis of foreign literature research. This article selects more than ten representative mistakes of Gogeum Seongnim and examines them, and on this basis, analyzes the reasons for the mistakes as errors caused by negligence in transmission and copying, negligence in sentence segmentation, errors in pronounce, and errors in form. From this, we can also glimpse the types and reasons of errors in the Chinese dictionaries in the Joseon period, which we wish to be helpful to the collation of and research on the Chinese dictionaries in the Joseon period.