Recently,a great exploration breakthrough has been made in shoal porous reservoir of Maokou Formation in northern Sichuan Basin.Based on the latest drilling and seismic data,the stratigraphy,sedimentology and geochemistry of Maokou Formation in northern Sichuan Basin has been studied.The results show that:(1)The slope facies is developed in Maokou Formation of Well JG1,which confirms the differentiation of platform and trough occurring in mid-late stage of member-2 to late stage of member-3 of Maokou Formation.(2)The middle and upper part of member-2 of Maokou Formation develops the lower slope subfacies,which is mainly composed of grey-black micrite limestone and silty limestone,with storm deposits,silicon interlayer and lamellation developed.The storm deposition sequences that can be recognized mainly include combination of erosion surface and biodetritus bedding,combination of biodetritus bedding and graded bedding,combination of erosion surface and biodetritus bedding and horizontal bedding,combination of erosion surface and gravel bedding.The member-2 of Maokou Formation develops upper slope subfacies,which consists of bioclastic micritic limestone and micrite bioclast limestone reflecting low-energy sedimentary environment,and the paleontology is a combination of shallow water organisms,with sediment structure of biological burrows and imbricated bedding developed.(3)The slope facies in the northern Sichuan Basin constitutes a continuous shallow sedimentary sequence in the vertical direction,and spreads along the Jiange-Langzhong line in a northwest direction.The slope and platform margin form the progradational sedimentary model of rimmed platform.(4)Organic geochemical analysis shows that the lower slope subfacies have a high abundance of organic carbon,among which tempestite is the best with TOC up to 15，,which has high-quality hydrocarbon generation potential.The study clarifies the period and plane position of platform and trough differentiation,and provids support for expanding the exploration of shoal porous reservoir of Maokou Formation.The discovery of high-quality hydrocarbon source rock in the lower slope subfacies can contribute to establish a variety of reservoir formation mode in the Maokou Formation,which is of great significance to evaluate the resource potential of the Maokou Formation in northern Sichuan Basin.