In view of the strong heterogeneity of tight sandstone reservoir in Upper Paleozoic He 8 in Yanchang area of Ordos Basin, the sedimentary microfacies and reservoir characteristics in this area are deeply studied by means of comprehensive application of core observation, logging facies analysis, thin section identification and physical property test. Three types of sedimentary microfacies, such as distributary channel, bay and mouth bar at the front of braided river delta, are identified, the distribution characteristics of porosity and permeability of reservoirs are clarified, and the influence of diagenesis on reservoirs is discussed. The results show that the porosity of the He 8 reservoir in Yanchang area is mainly 3.5%–9.6%, and the permeability is mostly lower than 0.5 × 10−3μm2, which belongs to ultra-low permeability reservoir. The type of sedimentary microfacies, carbonate cementation and dissolution pore development are considered as the main controlling factors of reservoirs. The research results are of great significance for understanding the reservoir characteristics and heterogeneity of the He 8 in Yanchang area, and provide scientific basis for subsequent oil and gas exploration and development.