Abstract: By adopting the method of geochemistry and sedimentary theory,and combined with elemental analysis,experimental technology means such as high resolution scanning electron microscopy(sem),the discussion on organic matter development characteristics,forming environment and en-richment factors have been carried out by taking Biyang sag,the typical continental fault lacustrine basin as an example,which provides a good guidance for shale oil exploration.Research results indicate the organic matter in the shale is the material basis of the formation of shale oil,which determines the hydrocarbon generation potential of shale and amount of hydrocarbon generation.The organic matter mainly comes from the planktonic algae;low development environment of organic matter is mainly for slow deposition,reduction of drought-semi-arid conditions,medium-high productivity saltwater lake environment.Amorphous organic matter is the main form of organic matter,and the organic matter in the pore is due to the effect of hydrocarbon generation of organic matter,which can provide effective reservoir space for oil shale.The paleo-environment determines the preservation conditions of organic matter,plane distribution of sedimentary facies have the control effect on the organic matter enrichment.