Abstract: During the exploitation of high-sulfur gas reservoirs, sulfur deposition occurs as the formation pressure decreases, leading to a reduction in reservoir porosity and permeability, which in turn restricts the efficient development of the gas reservoirs. Currently, research on the characteristics of sulfur deposition at the microscopic pore scale of reservoir rocks and its impact on reservoir physical properties remains relatively limited. In this study, the high-sulfur gas reservoirs in the Feixianguan Formation of the Luojiazhai area, composed of carbonate rocks, were taken as the research object. A sulfur deposition simulation experiment under actual formation conditions was conducted by comprehensively employing analytical techniques of nuclear magnetic resonance (NMR), computed tomography (CT) scanning, and scanning electron microscopy–energy dispersive X-ray spectrometry (SEM-EDS). The research indicates that after the sulfur deposition experiment, sulfur deposition occurs in the form of thin films covering the surfaces of rock grains, resulting in a decrease in the pore space of the rocks. Sulfur deposition is predominantly concentrated in small to medium-sized pores, with relatively less deposition in large pores. The pore-throat structure and morphology of the rock samples also undergo changes, with a significant reduction in the number of pores with diameters ranging from 0 to 100 μm, along with decreases in coordination number and tortuosity. Sulfur deposition leads to a reduction in the porosity and permeability of the rock samples, and the degree of damage exhibits a power-function relationship with the initial porosity and permeability of the rock samples. The poorer the physical properties of the rock samples, the greater the degree of damage caused by sulfur deposition. The BRIEF REPORT is available for this paper at http://www.ykcs.ac.cn/en/article/doi/10.15898/j.ykcs.202505060115.