P.3492v was a piece of Dunhuang fragment of the divination book specially for telling the moles of human being’s body which was dating from the Tang Dynasty. It recorded not only the placement of the moles around man’s body but the designation of the moles and telling the fortune and fate at the same time as well. So far, it is a unique divination book for moles with the richist contents and in the most details to be found and it has objectively reflected the actual development of the divination for moles in the Tang Dynasty and the true situation of its population among the folks of the historic times. This article is gong to make a preliminary study on P.3492 fragment by its writing style and the contents. The study is also going to take much refrences to the Chinese classical documetation and other relative materials with the same subject of divination found among the Dunhuang Manuscripts to make the study to be complete and prefect.