<p>During the operation of a deep shaft, a layer of surrounding rock may have already been in a failed (post-peak) state but is still subjected to loadings and unloadings. To ensure the safety of the shaft, it is important to understand the post-peak hydromechanical behavior of the surrounding rock. Therefore, this paper performs unique hydromechanical coupling tests to explore the permeability evolution of rock under post-peak cyclic loading and unloading. The results indicate that the rock becomes more permeable with the increase in post-peak loading–unloading cycles, and the increase of the permeability is less significant at a higher confining pressure. Moreover, the permeability of the rock decreases in the post-peak loading stage and increases in the post-peak unloading stage. The pore structure of the rock specimens before the test and after the post-peak loading and unloading cycles was also analyzed using NMR and SEM, respectively. The results indicate that the rock specimen after post-peak loading and unloading cycles contains more macropores (and/or open fractures), which explains why the permeability of rock has increased after post-peak cyclic loading and unloading.</p>