Based on core and cast section analysis, it is believed that Denglouku Formation in ChanglingGasfield is low porosity and lowpermeability reservoir. The rock type is mainly fine-grained feldspathic lithic sandstone, and the rock porosityranges from2.7% to6.6%. The reservoir space ismainly secondary pore, and the pore type ismainly intergranular dissolved pore. Rock texture, sedimentary environment and diagenesis are the main factors influencing the reservoir properties. The reservoir property of branch channel is relatively good, followed by the natural levee and crevasse splay, and it is the worst in the interchannel. The compaction, pressolution and cementation do great damage to the primary porosity of reservoir, while the dissolution is favorable for the forming of secondary pore and improve the reservoir property. The diagenesis in this area ismainly destructive to the reservoir property.