Abstract: The Jiufotang Formation in Sihedang area of Lingyuan City, Liaoning Province, is rich in Mesozoic Jehol Biota fossils, most of which are precious. Through section measurement, fossil collection and field survey, the formation is divided into three members, in which the distribution of fossil beds and occurrence horizon of significant fossils are determined, namely, Hanjiagou Bed in the first member, Saerdaowan Bed in the second member and Sihedang Bed in the third member. This result promotes the research level of the study area.