Abstract: The sporomorphs and charophyte fossils were previously discovered in the lower part of the Relu Formation of Eocene age.However,little has been known for the age of the upper strata of the Relu Formation.Recently,abundant sporomorphs have been recognized by the authors in the upper strata of the Relu Formation in the geological survey of the 1∶250 000 Mengshacun Sheet,resulting in the establishment of the sporopollen assemblage zone Lycopodiumsporites oligocenicus-Ephedripites(Distachyapites) eocenipites-Peltandripites davissii.The discovery of the above-mentioned sporomorphs allows the dating of the upper strata of the Relu Formation also as the Eocene.