Abstract: According to new data and previous research results in recent years, the characteristics of reservoir and caprock of the South Yellow Sea were comprehensively investigated. Ancient marine Mesozoic strata were chosen as the main hydrocarbon source rocks. Based on the tectonic movement and sedimentary development analysis, the hydrocarbon accumulation in marine Mesozoic strata of South Yellow Sea is divided into four stages: stages before Triassic indosinian movement, Jurassic-Cretaceous, Paleogene and Neogene. This paper shows that ancient marine Mesozoic strata in the South Yellow Sea have the prospect of hydrocarbon development, through the analysis of the characteristics of the reservoir. The favorable marine oil and gas resources accumulation were forecasted based on the study of the hydrocarbon source and preservation condition in later period. This study provides the basis for oil and gas exploration and makes contribution to the deployment of new offshore oil and gas in China.