Zizhou gas field is a multi-layer superposed tight sandstone gas field. The reservoir covers strata from Benxi Formation of Carboniferous system to He8 Formation of lower Shihezi Formation of Permian system. At present, the pore structure of the reservoir and its influence on the reserve utilization are not well understood. It seriously restricts the gas field interlayer digging process. The pore structure of tight sandstone reservoirs in Benxi Formation-He8 Member was comprehensively investigated through the utilization of cast thin sections, reservoir physical property, production data, as well as statistical and correlation analysis methods. The suggestions for further interlayer potential exploitation were also given. Draw four conclusions. The reservoir has a typical 1+1 type pore structure. Among them, the lower formations (Benxi Formation, Taiyuan Formation, Shan2 member) have developed primary intergranular pores, with large primary pore proportion, face rate and pore size, and good pore structure, which is the dominant pore structure of primary pores. In the upper formations (Shan1 member and He8 member), the intragranular dissolve pore- intercrystalline pore- microfissure are developed, the primary pore ratio, face ratio and pore size are smaller, and the pore structure is poor, which is the dominant pore structure of the secondary pores. The difference of rock composition, especially the content of quartz and cuttings, is the main reason for the formation of 1+1 pore structure. Among them, the lower formations are dominated by quartz sandstone with high quartz content and low cuttings content, which is conducive to the preservation of primary pores. The upper formations are dominated by lithic sandstone with high lithic content and low quartz content, which are not conducive to the preservation of primary pores but to the formation of secondary pores. The pore structure of 1+1 type has a significant effect on the exploitation of reserves. Among them, the lower formations have good pore structure, relatively high permeability (0.52 mD), large discharge area (0.70 km²), and high reserve utilization degree (67.9%). The upper formations have poor pore structure, relatively low permeability (0.33mD), small discharge area (0.34 km²), and low reserve utilization degree (26.9%). The analysis shows that the reserves of the upper formations have not been effectively utilized under the current well pattern conditions. In order to reduce the waste of reserves in the upper formation, realize the balanced exploitation of gas fields and improve the overall reserve utilization degree of Zizhou gas field, it is recommended to exploit the upper formations separately with a small well spacing.