Shaanxi－Gansu－Ningxia area is located at the western part of North China platform and the conjoining part of east and west tectonic area, and is one of the most important oilgasbearing area in China. Influenced by alternative tectonic background, eustatism and sediments supply, the Late Palaeozoic depositional system types are diverse. Through the synthetic study of field outcrops, well core, logging and mapping, depositional system types have been identified, including carbonate platform, barrier islandlagoon and tidal flat, tidal channellagoon and tidal flat, river delta, fan delta river, lake, alluvial fan systems. The distribution and filling evolution of the Late Palaeozoic depositional system were related closely with the tectonic activity of the Xingmeng Trough and the QinlingQilian Trough. Controlled by basement and basin marginal fracture, the aulacogen at the western border revived at the Late Carboniferous and formed estuary filling of tidal channellagoon and tidal flat deposits. At the Early Permian sea water of east and west parts joined together to form an united NorthChina epicontinental sea and the coalbearing deposits were formed in environments of carbonate platform, barrier island and shallow water delta in the study area. During the Middle－early Late Permian the epicontinental sea contracted and evolved into a paralic inland depression in the study area and alluvial fan, river, delta and lake facies were formed. During the late LatePermian the epicontinental sea extincted and this area evolved into an inland depression and formed riverlake fillings, mainly lake facies. The development of sandy reservior were controlled by sedimentary environments and its spatial distribution was controlled by palaeotectonic mechanism.