Abstract: In order to study the mineral characteristics of shale gas reservoirs, and analyze the influences of different minerals in shale gas reservoirs, in this pape r, by using X-ray diffraction ( XRD) technology, qualitative and quantitative analyses were performed on 17 shale samples from the Upper Permian Longtan Formation of Meishan Area, and it was put forward that, the difference of mineral composition results in the difference of shale reservoir performance. The results of research show t hat major components of the Longtan Formation mud shale Are composed of clay minerals and quartz, with an average of 49.1% and 30.6% respectively, the next is cal cite with an average of3.5%.In addition, a small amount of feldspar, pyrite, siderite and so on Are included. Clay minerals Are helpful for the adsorption of shale gas, brit tle minerals such as quartz and calcite Are in favor of width generation by fracturing in the process of exploiting. The component and content of the mineral have influen ce on the adsorption capacity and retrofit of shale gas reservoirs.