Hou ke mi yao (Secret Key of Laryngology) was one of the most popular books of throat department in the Qing Dynasty. Because of the inscription "Xiyuan Zheng of ancient She as the author, Xu Zuo-ting of Lequan revised and enlarged", this book was generally regarded as the important work of Xin'an Zheng's family of throat department. However, after the textual research, Hou ke mi yao, in fact, was edited on the basis of Zhang Zong-liang's Hou ke zhi zhang (Guide Book for Laryngology) of the Qing Dynasty: with the second volume, "method of processing" deleted, and Wu's "verse of 24 kinds of symptom of throat diseases" (his whole name unknown) and 12 pills added. Thus, the author of Hou ke mi yao was Zhang and Wu instead of Xiyuan Zheng, and the contents reflected the academic thought of Zhang Zong-liang and Wu. According to the record of General Catalogue of the Ancient Literature of Chinese Medicine in China, there were 14 editions of Hou ke mi yao available, however, only 12 editions are extant after the investigation. In addition, there are mistakes of its author, book title and editions included in the Textual Research on Chinese Medical Literature and General Catalogue of the Ancient Literature of Chinese Medicine in China which, therefore, should be corrected.