Abstract: The third member of the Denglouku Formation is a prospect area for the oil and gas resources in the Xujiaweizi subsidence, Daqing, northeastern China. In this paper, the lithology and sedimentary facies are discussed, and sequence stratigraphic cycles and their systems tracts am discriminated on the basis of sedimentary facies, lithology and well logs. The classification has been verified by using Fischer's plots, which may be a potential tool for sequence analysis.