Abstract: It is of practical significance in accelerating the progress of natural gas exploration and deve-lopment to analyze controlling factors and spatial distribution patterns of high-quality reservoirs.Major controlling parameters of diagenesis and diagenetic facies on spatial distribution patterns of high-quality reservoirs of Upper Paleozoic in the eastern Sulige Gas Field of the Ordos Basin are discussed in this paper,based upon detailed description and observation of drilling cores,accompanied with various analytical and measurements including identification and quantitative statistics of thin sections under microscope,grain size analysis,electron scan microscope(ESM),capillary pressure analysis and measurement of homogeneous temperature for inclusions.Research shows that detrital grain size,sandstone types and diagenetic differences of sandstones are the main controlling factors for reservoir quality.Nine diagenetic facies can be recognized.The quartz overgrowth cementation mixture pores diagenetic facies,authigenic kaolinite cementation inter-crystal pores diagenetic facies,and clay matrix filling dissolution facies distributed between dense diagenetic facies are the most profitable diagenetic zones for high-quality reservoirs.Micro-fractures and dissolution are the key parameters for high-quality reservoirs formation.