Abstract: In this paper,the studies of geochemical characteristics on both the Jurassic sourcerocks and oil-bearing sandstones in the fault depression of the southeast Tarim basin havebeen carried out.It is suggested that the kerogens of the Jurassic source rocks mainly comefrom nonmarine higher plants with low evolutionary level while those of the Jurassic oil-bearing sandstones derived from lower hydrobios with high maturity of crude oil. Therefore,it is revealed the source rocks of the Jurassic oil-bearing sandstones should be attributed to Paleozoic marine source rocks.