Abstract: By means of the core thin section, cast thin section, SEM and X?ray diffraction analyses and the sedimentary facies researches, it is indicated that the Toutunhe ?2 member sandstone reservoir in Fudong slope area of Junggar basin underwent destructive compaction, pressolution and cementation, as well as constructive inhibition effect of early edge?distributed clay film on quartz secondary overgrowth and cement precipitation during its diagenesis. From analysis of diagenesis types and evolutionary sequence, it is considered that the major diagenetic evolution of the reservoir is in the late of diagenetic Stage?B, partial in the early of diagenesis Stage?A. Also, on the basis of establishment of diagenetic evolution model, such 4 types of diagenetic facies are classified as film?pore type, rich calcite cemented?pore type, rich kaolinite cemented ? pore type and strong compaction ? pressolution type. They are all controlled by sedimentary micorfacies, diagenetic fluid property and activity, and the oil?gas productivity here is related to the diagenetic facies types