This study aims to investigate the mechanical properties and acoustic emission characteristics of sandstone with different moisture contents under the action of wet-dry cycles. The sandstone samples were sourced from the surrounding rock of a subway station tunnel project in Chongqing. The samples underwent 0, 10, 20, and 30 wet-dry cycles, and the tests were conducted by controlling the moisture content of the sandstone at different cycle stages (dry, 1.2%, 2.4%, 3.6%, and saturated). Uniaxial compression tests and acoustic emission monitoring were performed, along with Scanning Electron Microscope (SEM) analysis to examine the microstructure of sandstone after different numbers of wet-dry cycles. The results indicate that as the number of wet-dry cycles increases, the pore structure of the sandstone becomes more complex, with increased cracks and the detachment of crystal particles, leading to pronounced microstructural deterioration. The uniaxial compressive strength of the sandstone decreases, and the impact of moisture content on strength becomes more significant. Additionally, the increase in wet-dry cycles and moisture content significantly reduces the level of acoustic emission activity during the failure process, while also mitigating the degree of fragmentation, reflecting the weakening of internal microfracture expansion and energy release. The study reveals a synergistic effect of wet-dry cycles and moisture content on the deterioration mechanism of sandstone.