Abstract: Under scanning electron microscope with an amplification of 5,000-10,000 X,organic nanofossils of marine primitive organisms have been discovered for the first time.They are found in the amorphous kerogen of Lower Paleozoic black claystones of deep water basinal facies and darkgrey impure carbonate rocks of deep water shelf facies at southern margin of Yangtze Para-platform.It is suggested that they belong to a new kind of organic nanofossil.This discovery not only provides direct information for deviding the types of source material and for characterizing its components in this highly mature area,filling up the blankness of such a kind of study,but also adds new data to the study of paleo-environment,paleo-geography and organic facies.This discovery changes the traditional concept,and reveals the actual aspect of source material.