PAN style="FONT-FAMILY: ’Times New Roman’,’serif’" lang=EN-US>///With focus on the geo-chemistry and reservoir petrology, a preliminary study is performed on the geological conditions of shale gas forming in the three Paleozoic organic-rich shale strata in Subei area, including the lower Cambrian Mufushan Formation, the upper Ordovician Wufeng Formation, the lower Silurian Gaojiabian Formation, the Permian Formations (Gufeng Formation, Longtan Formation, Dalong Formation, by using core, drilling and outcrop data. The results indicate the Paleozoic shales are widely distributed in Subei area, relatively thick, organic rich, and higher thermal mature.