Abstract: The basin within the continental shelf of east China Sea was subjected to regional tectonic events during the period from late Cretaceous to Quaternary, which experienced four sedimentary cycles, including three sedimentary cycles of transgression-regression and one transgressive sedimentary cycle, correspondingly, three complete suites of oil and gas assemblages and one suite of natural gas assemblage were developed on the middle and lower parts of sedimentary cycles.The petroliferousness is of the best for the oil and gas assemblages from upper Cretaceous to Eocene as being proved by drilling.Pinghu oil-gas field and a number of oil-gas structures have already been discovered.