Abstract: Based on the newly acquired and reprocessed seismic data, in combination with drilling data, gravity and magnet inversion and onshore and offshore correlation, the authors studied the geological characteristics of Mesozoic and Cenozoic strata in southern East China Sea Shelf Basin. With sedimentary center in the east, the Mesozoic strata of great thickness are distributed extensively over such uplift areas as Taibei, Guanyin and Yandang. The Cenozoic strata are thicker in the east and west than in the central part in the study area. The southern East China Basin was a marginal depression basin in Mesozoic, with a western boundary of Jurassic on the east side of Yandang uplift, and that of Cretaceous on the west side of Oujiang Sag. More marine facies marks were found in drilling analysis, which shows that the transgression from south to north and from east to west happened in Jurassic, and that from east to west occurred in Cretaceous, in consideration of surrounding sedimentary environments. Source rocks of Lower Jurassic, Lower Cretaceous, Paleocene, Eocene, Oligocene and Miocene are well developed in the study area, so there exists a great hydrocarbon potential in the study area.