Based on the latest re-processed and newly acquired seismic data and using the integrated approaches including seismic, well drilling, inverse gravity and magnetic processing and land sea correlation, the authors studied the distribution of the Mesozoic in the southern East China Sea Shelf Basin, and got some new understandings about the three uplifts, namely the Yandang, Taibei and Guanyin uplifts, defined by previous studies. The results show that the Mesozoic strata in the Southern East China Sea Shelf Basin are quite thick and widely distributed. According to our data, it is thicker in the south and east, and thinner in the north and west. In this regard, the concept of Mesozoic Great East China Sea is proposed in this paper to conclude the new discoveries.