Abstract: In the lower combination in southern margin of Jungar basin mainly developed three sets of major reservoirs: the Kalaza formation and the Qigu formation of Upper Jurassic and the Qingshuihe formation of Lower Cretaceous, with the main rock types of feldspar lithic sandstone and lithic arkose, and the overall properties of low compositional maturity and medium-high textural maturity as well as weak diagenesis (in the early diagenetic stage of A and B). The pore types are dominated by residual original intergranular pores and fewer dissolved pores. The whole reservoir is characterized by the deep-burial and high quality. The cumulative thickness of the three sets of reservoirs with the characteristics of regional distribution generally exceeds 100 m, some area up to 250~300 m, and most of the area has two and three sets of overlapping