Middle-late Permian tight fluvial sandstone is the most important reservoir sequence in the Upper Paleozoic of Bohai Bay Basin. Based on field investigation of geological profile，analysis of logging data，thin-section identification as well as core observation and description，the sedimentary evolution and sandstone distribution of middle-late Permian fluvial facies in the study area were analyzed in detail. As a result，the middle-late Permian fluvial sediments mainly developed in Lower-Upper Shihezi Formation in Bohai Bay Basin with sand-rich Heishan Member，Wanshan Member，and Kuishan Member from bottom to top. A set of purple-red siliceous clastic sedimentary formation developed，featuring various rock types and colors，well-developed beddings，and strong hydrodynamic conditions for sediments. The Lower Shihezi Formation consists of meandering river deposits with developed marginal beaches，embankments，and flood basins but limited distribution of sandstones. With regard to the Upper Shihezi Formation，Wanshan Member gradually evolves to the braided river. Alternating sedimentation of channel bar，river channel，and flood basin and the number of layers and size of sandstone are both larger than those in the Lower Shihezi Formation；the clastic material supply of the source area in Kuishan Member was enhanced during the sedimentary period when the study area was characterized by braided river channels and channelbar deposits，forming a paleogeographic pattern of“basin full of sandstone”. The accumulated fluvial sandstone thickness in the residual framework of Lower Shihezi Formation in Bohai Bay Basin is generally less than 80 m，while the accumulated thickness of Wanshan Member-Kuishan Member of Upper Shihezi Formation is generally 40-120 m. Three thickness centers were developed in Jiyang Depression，Eastern Jizhong Depression-Huanghua Depression，and Central and Western Linqing Depression. The research results provide new technical support for oil and gas exploration and target optimization in Bohai Bay Basin in the Upper Paleozoic.