| In order to explore the characteristics of Chang 4+5 reservoir in Jingbian area, Ordos Basin, the characteristics of Chang 4+5 reservoir were studied and analyzed by casting thin section, scanning electron microscope and mercury injection experiment, and a comprehensive classification standard suitable for chang 4+5 reservoir was established. It is found that the reservoir lithology is mainly fine grained arkose and a small amount of lithic arkose, and the interstitial materials are chlorite, Aemon mixed layer and calcite, etc. The pore types of the reservoir are mainly intergranular pores and dissolution pores, and the total face rate is 4.7% on average. The throat is mainly sheet and curved. The pore-throat combination type is small-medium pore and large-throat type, the average porosity is 11.95%, and the average permeability is 0.84×10-3μm2, which belongs to the low-medium pore and ultra-low permeability tight sandstone reservoir. The pore-throat structures in the study area were classified into class I macropore-rough throat, Class II meso-rough throat, class III fine-pore-fine throat and class IV fine-pore-micro throat. Based on multiple factors, chang 4+5 reservoir in the study area can be divided into class I high quality reservoir, Class II medium reservoir and Class III general reservoir, accounting for 28%, 49% and 23%, respectively.