Abstract: Oil shale is distributed all over China, concentrating in Mesozoic and Cenozoic basins. It is mainly distributed in extensional basins, flexure basins, strike-slip basins and cratonic basins in accordance with basin type, and extensional oil shale basins are in the majority. Through the study on the extensional oil shale basins in Northeast China, this paper emphasizes on the formation law of oil shale in Songliao Basin and Dalianhe mining area of Yilan Basin, sums up the factors controlling the formation of oil shale deposits in the extensional basins in Northeast China. The formation of oil shale deposits is mainly affected by the sedimentary environment, paleostructure, paleoclimate, organic matter sources, redox conditions, paleotopography, paleosalinity, etc. The study on the formation law of oil shale deposits in extensional oil shale basins has promoted the development of China's geological theory of oil shale and the exploration and development of similar oil shale basins