The author has analysed 561 microfossil samples from eighteen drill holes inthe north part of the continental shelf of the South China Sea, and has foundCharophytes, including Characeae, Clavatoraceae and Vegetives. Based on the fea-tures and distribution of the Charophytes, Lower Cretaceous, Upper Cretaceous, Pale-ocene, Oligocene and Neogene strata may be distinguished. Among other things,the charophytes and lithology of the Lower Cretaceous, Upper Cretaceous andPaleocene strata may be correlated with those of the Lower Gretaceous GuancaohuGroup, Upper Cretaceous Dalangshan Formation and Paleocene Buxin Formationand Xibu Formation in the continent of Guangdong Province. It is indicated thatboth were connected in the period from the Gretaceous to Paleocene, and havethe same or similar paleogeography and depositional euvironmend. After the EnpingFormation was deposited, the crust rose and then there occurred differentiation.The Pearl River delta no longer sank after the Lower Eocene Huayong Formationwas deposited, and the north part of the continental shelf of the South ChinaSea began to sink at the beginning of the Oligocepe until it formed the present-day South China Sea.