Abstract: The thin sections of Devonian Donghetang sandstones from several typical wells in Bachu-Maigaiti area of the Tarim Basin were observed.In the Donghetang Formation,quartz was in high content while feldspar and lithic ranged from 1% to 4%,standing for high maturity.The main diagenetic effects included compaction,cementation,dissolution (dissolving) and so on.Devonian Donghetang sandstones were during the middle and late stages of diagenesis.Few primary pores and fissures were found.Epidiagenetic dissolution and burial dissolution dissolved a variety of soluble and carbonate rocks,resulting in intragranular dissolved pores,moldic pores and enlarged dissolved pores.However,since the process of diagenesis was superimposed in the study area,the improvement of reservoir was limited and the physical property of Devonian Donghetang Formation was poor.