The study of diagenetic characteristic about reservoir rocks is one of the core issue to the reservoir research,and it is essentially prior to reservoir evaluation and prediction. In this paper,various diagenesises occurredin Xujiahe sandstone are analysed by slices samples which are systematically and carefully observed. The genesisand its effect on the pore developing are discussed in the diagenesis stages later,based on which the diagenesisphases of sandstone in Xujiahe Formation are classified in the st...