The tight sandstone gas reservoir in the eastern region of the Ordos Basin has strong heterogeneity and is difficult to develop. This study focuses on the tight sandstone gas reservoir in the Jiaxian area of the eastern Ordos Basin. Through methods such as core observation, thin section identification, high-pressure mercury intrusion, X-ray diffraction, and clay minerals. The conclusion drawn from the research is that: There are certain differences in rock types among different layers in the Jiaxian area. The quartz in Shan1 + Shan2 Sections, and He8 Sections is lower, and lithic quartz sandstone and lithic sandstone are more developed. The Ben1-Ben3 Section and Tai1 + Tai2 Section have higher quartz content, with more developed quartz sandstone and lithic quartz sandstone. The He8 Section is mainly composed of dissolution pores, intergranular pores, and microcracks. The Shan1 + Shan2 Sections and Tai1 + Tai2 Section have more developed dissolution pores, while the Ben1-Ben3 Section has better developed dissolution pores and intergranular pores. The mercury injection curve of He8 and Shan1 Section is relatively steep, and the pore throat sorting is relatively poor. Shan2 Section and Tai1 + Tai2 Section are second, while the mercury injection curve of Ben1-Ben3 Section is relatively gentle, and the pore throat sorting is the best. The permeability of reservoir is 0.60 mD, and the porosity of the reservoir is 7.6%. The He8 Section and Shan1 + Shan2 Section are in the early stage of moderate diagenesis. The Tai1 + Tai2 Section and Ben1-Ben3 Section are in the late stage of moderate diagenesis. The research results provide support for the effective utilization of tight sandstone gas reservoirs in the Jiaxian area.