Abstract: The Middle Jurassic is one of major source rocks in the northeastern Kuqa depression for it has a typical continental shale, and it is of good potential of shale gas generation. The study of characteristics of the shale gas reservoir from X?ray diffraction, scanning electron microscope and argon?ion polishing techniques that its organic matter?rich shale mineral components are mainly composed of quartz (18%~55%) and clay minerals (9%~76%), the latter are dominated by illite/smectite mixed layer and illite, with the shale porosity of 0.5%~7.3% and permeability of less than 0.1mD, belonging to a supper?low porosity and ultra?low permeability reservoir; The shale reservoir spaces mainly include nano?micron mineral matrix pores, organic micro?pores, structural micro?fractures and diagenesis micro?fractures. Comparing with the typical gas?bearing shales in North America, the Middle Jurassic shale is of similar reservoir characteristics and could be faverable shale gas reservoir. Also, the research shows that the mineral composition，diagenesis and structural process mainly influence the characteristics of the reservoir in this area. It is suggested that the gas?bearing nature and the modifiable property of the Middle Jurassic shale are paid more attention to in next?step researches and further exploration and exploitation