At present, the world's energy development is transforming from fossil energy to new energy, and natural gas as a clean fossil energy is the best choice for the transition. The Shanxi formation in Yan 'an area of Ordos Basin is a layer with great exploration potential of continental shale gas in China, and great exploration and development achievements have been made in recent years. To further deepen the geological understanding of the area, Taking the mud shale of Shanxi Formation in Yan 'an area of Ordos Basin as the research object, the rock types, lithofacies types and sedimentary facies distribution of Shanxi Formation are studied by using outcrop, core and well logging data. The results show that the shale of Shanxi Formation in Yan 'an area mainly develops four lithofacies types, namely, argillaceous siliceous shale (S-3), claystone (CM), calc/siliceous clay shale (CM-1) and calc/clayey siliceous mixed shale (M-2). There are four rock types: shale, silty mudstone, carbonaceous mudstone and fine grained sandstone. Shore-shallow lake subfacies, delta front subfacies and pre-delta subfacies are developed, and the sand bodies of underwater distributary channels in the study area are developed in a north-south belt. According to the maturity of organic matter (Ro), organic carbon content (TOC) and thickness of dark mudstone, the lithofacies can be further divided into three types. Among them, type I lithofacies is favorable for oil and gas exploration, mainly distributed in the eastern and northern Yanchang area of Shan-1 member, and Shan-2 member is mainly distributed in Xiasiwan area of Ganquan.