Abstract: The shale of Lower Cretaceous is uniquely verified to be source rock in B basin of Central Africa region. The geochemistry study indicates that the source rock in B basin is characterized by high organic matter abundance with II1 type of organic matter, being a good hydrocarbon source rock. Influenced by the tectonic inversion, erosion and high geothermal gradient, the present depths of hydrocarbon generation threshold are usually shallower than the normal. From NWW to SEE, the depth of threshold becomes deeper. The shale of lower Aptian stage and Barremian stage of Lower Cretaceous is the effective source rock. The oil and gas in shallow zone of slope belt in northern B basin undergo biodegradation, and have obvious relativeness with oils in deeper zone by analyzing their biological markers. It is predicted that there exist several oil kitchens in B basin.

Key words: Central Africa region, B Basin, geochemistry, characteristic, source rock, Lower Cretaceous