Abstract: Research on the Paleogene source rocks in the Lishui-Jiaojiang Sag (LJS) of the East China Sea Shelf Basin focuses on mainly the lacustrine source rocks of the Yueguifeng Formation, while the formation conditions and distribution patterns of high-quality marine source rocks of the Lingfeng Formation are not yet clear. Based on the comprehensive utilization of geological, geochemical, and paleontological data, and the analysis of organic geochemical characteristics of source rocks, we explored the main controlling factors for the development of marine source rocks in the Lingfeng Formation of the LJS, and their formation patterns and distribution. Results show that the Lingfeng Formation in the LJS developed moderate to good grade terrestrial marine source rocks, and different internal sags have strong heterogeneity. The development of hydrocarbon source rocks is comprehensively influenced by factors such as paleoproductivity, source input, and hydraulic conditions. From a planar perspective, the scale and quality of the source rocks in the LJS are closely related to the sedimentary environment of the deltaic coastal shallow sea. The delta front and near-delta shallow marine facies have a large amount of terrigenous organic matter input., and high abundance source rocks are developed in a weak oxidation weak reduction environment, which is a favorable facies zone for the development of high-quality source rocks in the Lingfeng Formation.