According to seismic, well-logging and core data, the micro-facies and type of the third member of Paleogene Hetaoyuan Formation in Bidian area of Biyang sag were determined on the basis of sedimentary structures, lithological textures of profiles and thicknesses of sandstone bodies. It is shown that there exist widely-distributed deposits of turbidite fans and sliding turbidite fans characterized by the turbidity-flows sediments, and sedimentary frameworks of north and south turbidite fans interbedded with the deep-water lacustrine sediments at the center. Sedimentary evolution, rich early turbidite sandstones and late deep-water mudstones suggest relative rise of the lacustrine level. oft-com:office:office" />