xygendeficient environment is an important condition for formation and preservation of marine source rocks. The study of paleoxygenation facies is significant for tracing spatialtemporal distribution of highquality marine source rocks and interpreting the evolution of depositional environments. During the Devonian， carbonate platform(nearshore and isolated platforms)and inner platform taphrogenic trough resulting from intracontinental rifting were simultaneously developed in the southern South China Sea. The Devonian paleoxygenation facies types are controlled by seawater layering in platform troughs and the QinzhouFangcheng taphrogenic trough， where quasianaerobic and anaerobic facies were dominant. The paleoxygenation facies is controlled by sealevel changes in platform in which developed aerobic and dysaerobic facies. Siliceous， phosphorus and organic carbonrich deposits of the Devonian indicate the upwelling flows influence. The southern South China Sea was located in the tradewind zone near the equator in the Devonian. Westward surface ocean current passed over the southern South China Sea and formed offshore currents. Eastward bottom current compensated toward shore and formed the upwelling flow. The Devonian upwelling flow led to the formation of an oxygendeficient environment in the southern South China Sea.