Abstract: The South Yellow Sea Basin is the main body of the Lower Yangtze area, where marine Mesozoic-Paleozoic strata are widely distributed. The characteristics of source-reservoir-seal assemblage of the marine Mesozoic-Paleozoic strata in the South Yellow Sea Basin were analyzed by comparing the characteristics of hydrocarbon source rocks, reservoir and cap rocks, and combining with seismic sections, drilling and outcrop data. Four sets of hydrocarbon source rocks developed, including the Lower Cambrian Hetang and Mufushan formations, the Lower Silurian Gaojiabian Formation, the Lower Permian Qixia Formation, and the Upper Permian Longtan and Dalong formations. By comparing the characteristics of hydrocarbon source rocks of the Yangtze land area, the source rocks of the South Yellow Sea Basin may be classed as good hydrocarbon source rocks. Carbonate is the main reservoir type in the South Yellow Sea area, and there are four carbonate reservoir types: porous dolomitic, reef-bank, weathered crust and fractured. The marine strata of South Yellow Sea Basin developed three sets of regional cap rocks and three sets of complete assemblages. The South Yellow Sea Basin has very good oil and gas prospects.