Abstract: Carboniferous strata in the Muli area,Sichuan,are a complex of regional low-grade metamorphic carbonate rocks,argillaceousrocks, siliceous rocks and small amount of clastic rocks,yielding fossils such as conodonts , ammonites, fusulinids and corals. Nolithostratigraphic unit has been set up for it. Through sorting stratigraphic units,the author found that this complex has an intacttop and bottom,a distinct stratigraphic succession and clear contact relationships,yielding certain fossils.So with the Qingyi sectionof Muli as a holostratotype section,a new lithostragraphic unit──the Qingyi Formation──has been established for it. This paperdescribes the section of the Qingyi Formation.