Abstract: The exploration and development of oil and gas resources in the Carboniferous-Permian system of the Upper Paleozoic in Jiyang Depression have continuously achieved new breakthroughs, demonstrating that the clastic rock reservoirs in this area possess good potential for oil and gas exploration. However, the research level on reservoir physical properties, diagenetic characteristics, and controlling factors of reservoir development remains relatively low. The characteristics and main controlling factors of the development of clastic rock reservoirs in the Upper Paleozoic were studied through technical means such as core observation, rock thin section identification, and physical property testing. The results indicated that the sandstone lithology of the Upper Paleozoic Benxi Formation in Jiyang Depression was primarily composed of feldspathic lithic sandstone and lithic feldspathic sandstone. The sandstone lithology of Taiyuan Formation was mainly lithic quartz sandstone. The sandstone lithology of Shanxi Formation and Lower Shihezi Formation was primarily composed of lithic feldspathic sandstone and feldspathic lithic sandstone. The sandstone lithology of Wanshan Member of Upper Shihezi Formation was dominated by lithic sandstone, Kuishan Member was enriched in lithic quartz sandstone and quartz sandstone, and Xiaofuhe Member developed a single type of lithic sandstone. The reservoir space types of sandstone reservoirs in various formations of the Upper Paleozoic mainly included intergranular pores, intergranular dissolved pores, intercrystalline micropores, and fractures. Among them, intergranular dissolved pores were the most developed and served as the most important reservoir space. In Jiyang Depression, the porosity and permeability of the Upper Paleozoic Carboniferous-Permian clastic rock reservoirs increased from Benxi Formation to Upper Shihezi Formation, but they decreased again to Shiqianfeng Formation. In the uplifted and shallow sag tectonic style of the Mesozoic, the reservoirs had lower compaction and better physical properties compared with the deep sag tectonic style. Compaction and cementation significantly restricted the formation of dominant reservoirs in sand bodies of various formations in the Upper Paleozoic. The reservoirs lacked favorable dissolution targets such as carbonates and feldspar, and weathering and leaching had limited improvement on the reservoirs. Before the deposition of the Mesozoic, there were erosion areas in Dawangzhuang area and the east of Yihezhuang uplifts Guxi fault zone, and Wangjiagang area. The areas surrounding these erosion zones were favorable exploration zones for the Upper Paleozoic. Research on the genetic mechanism of high-quality reservoir development and the evaluation of favorable exploration zones could promote efficient exploration of the Upper Paleozoic oil and gas reservoirs in Jiyang Depression.