Abstract: In order to further make certa in the oil-gas accumulation phases of Bohu sag in Yanqibasin, we determined the oil-gas accumulation phases by testing the reservoir minerals and the fluid inclusions, ana lyzing the autogenetic illiteiso topeage, and using other research achievements. The fluid inclusions of Jurassic reservoir in Yanqi basin of Northwest China are mainly distributed in Sangonghe Formation and Badaow an Formation, with its homogeneous temperature mostly being 101～110℃ and 121～130℃. In it sinclusion component, the N-alkene Carbon atomic numbers show a bimodal shape, with the first peak being 18 or 20 and the latter peak being 26 or 27. These characteristics indicate that the basin had two periods of oil-gas accumulation during the mid-late Jurassic Period, with the first period being the mid-late Jurassic when the source rocks were in a low mature stage and the second period being the end of Jurassic when the source rocks were in a mature stage.