Abstract: The Upper Cretaceous Taipinglinchang Formation is the key oil-gas exploration horizon in Sunwu-Jiayin Basin. Based on the detailed field observation and description, the sedimentology of section of Taipinglinchang Formation in the east of the basin is studied in this paper. The results show that the sedimentary facies developed in Taipinglinchang Formation include lacustrine facies and fan delta facies, which can be further divided into 3 sedimentary subfacies with 6 sedimentary microfacies. The petrology and organic geochemical characteristics of the shale in Taipinglinchang Formation are analyzed by various organic geochemical testing methods. The results indicate that the mineral composition of shale is mainly quartz, belonging to felsic shale. The maceral composition is dominated by sapropelinite, with oil-prone property. The source rocks are of medium-good quality, with the organic matter types of Ⅱ₁-Ⅱ₂, which are in the low mature-mature stage, suggesting a good hydrocarbon potential. The results may provide basic data for further research and oil-gas exploration in the basin.