A century stratigraphic investigation of the oil- and gas-bearing Yanchang Formation in the Ordos Basin has generated numerous schemes of stratigraphic subdivision and correlation. For the purpose of oilfield development, the subdivision of oil- and gas-bearing sequence should be based on lithostratigraphy. The Yanchang Group includes sediments deposited in lacustrine and fluvial environments in the middle-late Triassic Period in the Ordos Basin. We propose that the oiland gas-bearing sequence of the Yanchang Group can be subdivided into ten oil- and gas-bearing formations (Changl-Chang20). Of these formations, the Chang2 can be subdivided into three oil and gas-bearing members (Chang2^1-Chang2^3). The Chang2^1oil member can be further divided into three compound oil and gas-bearing layers and several single layers. The detailed stratigraphic study of the Chang~ oil member is a key to the oilfield development in the area.