Abstract:The gas shales coexist with coals within the Permian Shanxi Formation at the northern Ordos Basin. The shales have relatively huge hydrocarbon potential with high total organic content (TOC). To characterize depositional microfacies on the gas shale distribution, lithofacies and depositional microfacies were investigated based on data of wireline log, gas log, core description, thin-section, grain size analysis, X-ray diffraction analysis for minerals of whole rock and TOC analysis. Seven lithofacies were recognized: (gray) black carbonaceous shale, (gray) black carbonaceous-bearing shale, (gray) black carbonaceous-bearing silty shale, (deep) gray carbonaceous-bearing shale, (deep) gray shale, (deep) gray silty/sandy shale and calcareous-bearing shale. These lithofacies were deposited in environment of plant-rich swamp, plant-poor swamp, intertitributary pool on delta plain, interchannel pool on floodplain, levee and distal crevasse splay. The plant-rich swamp and plant-poor swamp neighbored with peat swamp or peat flat which develops coals, and were often discovered within the Second Member of Shanxi Formation. The plant-rich swamp and plant-poor swamp are favorable depositional microfacies of gas shale reservoir because they take control over distribution of favorable gas shale lithofacies which include (gray) black carbonaceous shale, (gray) black carbonaceous-bearing shale, (gray) black carbonaceous-bearing silty shale and (deep) gray carbonaceous-bearing shale and have higher TOC than other lithofacies types.