In order to study the organic matter enrichment characteristics of the Permian Lucaogou Formation in the Shitoumei area of the Santanghu basin (NW China), total organic carbon analysis, rock pyrolysis, major and trace elements determination were carried out based on the detailed observation of cores and systemic sampling. The results show that the mudstones of the Lucaogou Formation in the Shitoumei area of the Santanghu basin have a high abundance of organic matter, the maximum TOC can reach 124%, and the maximum hydrocarbon generation potential (S1+S2) is 9441 mg/g. The main types of organic matter are type Ⅰ and type Ⅱ. The organic maturity is low, mainly immature to lowmature.The initial paleoproductivity of the Lucaogou Formation in the study area was medium, the paleotemperature was high with deep water. It was a semideep lake to deep lake environment. The water of the sedimentary period of the Lucaogou Formation was mainly stagnant with anoxic reduction conditions and high salinity. According to the geochemical parameters, the Lucaogou Formation in the study area can be divided into three layers from bottom to top. Comparing the changing paleoenvironment characteristics in these three layers, it is found that conditions of low hydrodynamic deepwater anoxic reduction, suitable warm climate conditions, suitable brackishsaline conditions and high initial paleoproductivity are conducive to the enrichment of organic matter, resulting in formation of oil shale. Optimization of internal layers of layer B shows that B3 interval is the most favorable development interval of oil shale.