Abstract: The Bikou Group is a sequence of rift margin type deposits occurring between the platform and rift. Various types of rock show features of regular facies change. On the basis of rock types and rock associations, it may be divided into 7 lithostratigraphic units of formation rank. This group rests unconformably on the Silurian Maoxian Group or Shuijing Formation and is in turn covered by the Middle Devonian Carboniferous Lueyang Formation, and contains such fossils as Amphissites pulcher, Bairdia sp., Desquamatia sp. and Schizo phoria sp. So its age is determined to be Early Middle Devonian.