<p>In the exploitation of deep mineral resources, surrounding rock is often subjected to coupled effects of water and stress disturbances, leading to damage and failure. Therefore, this study experimentally investigates the mechanical properties and acoustic emission characteristics of sandstones with varying water contents under deep mining disturbance conditions. The results show that the strength evolution of sandstone with water absorption time can be divided into three stages: steady softening, rapid softening, and slow softening. A quantitative relationship between strength and water absorption time was established. With increasing water absorption time, the proportion of micropores first increases and then decreases, mesopores initially decrease and then increase, while macropores show a continuous decreasing trend. Structural changes induced by the swelling of clay minerals and partial dissolution of other minerals lead to pore development, reduced cohesion, and weakened strength. Based on these observations, a microstructural evolution model of sandstone during water absorption was proposed. The variation in the proportion of low-frequency, high-amplitude acoustic emission signals reflects the evolution of crack propagation scales. As water content increases, the energy storage capacity of sandstone and its ability to generate acoustic emission signals both decline, resulting in a reduced likelihood of large-scale failure. Additionally, with increasing water content, the fractal dimension of sandstone fractures decreases, indicating a reduction in failure severity. The failure mode is dominated by shear failure, but the proportion of shear cracks decreases with higher water content.</p>