Shale gas,as a kind of new energy with its source and reservoir in the same strata,is rich in organic-rich shale widely,the study in the sedimentary characteristics and developmental of the organic-rich shale can provide geological basis for shale gas exploration.In this paper,we focus on the research of Wufeng Formation of the Upper Ordovician-Longmaxi Formation of the Lower Silurian in southeast Chongqing,using geochemical,sedimentology and combination with the tectonic background,analysis the sedimentary characteristics and affecting factors of Wufeng Formation of the Upper Ordovician-Longmaxi Formation of the Lower Silurian comprehensively.The study of main elements and trace elements show that,n (Al2O3)/n (Al2O3 + Fe2O3) value is between 0.69~0.78,with an average of 0.75,n (V)/n (V + Ni) value between 0.49 to 0.93,with an average of 0.73,The sedimentary environment of Wufeng Formation of the Upper Ordovician-Longmaxi Formation of the Lower Silurian is reducing marine environment,and developing a whole second-order sequence cycle,deposited deep-water shelf facies,shallow muddy shelf facies and shallow sandy shelf facies.because of the influence of the east side of xuefeng uplift in the study area,the water level from the south east to north westgradually deep,sand content gradually less,finally,through the vertical contrast of TOC content,The best exploration potential is deep-water shelf facies carbonaceous shale shale gas.