Based on the new seismic data and other data of geology, geophysics and geochemistry collected from the South Yellow Sea Basin and surrounding regions, the authors discussed in this paper the petroleum geologic characteristics of the South Yellow Sea Basin, and prospecting targets for marine strata were selected. The study results suggested that marine Mesozoic-Palaeozoic strata have a steady distribution in the study area with thick residual deposits including 4 suites of source rocks, 2 categories of reservoirs, 4 suites of mudstone cap rocks, which form favorable source-reservoir-cap assemblages for the formation of hydrocarbon accumulations.