Abstract: To investigate the effects of cyclic loading on pore-fracture structure and seepage characteristics of coal, cyclic loading tests were carried out using a coal-rock multiphase and multi-field triaxial dynamic seepage experimental system. The evolution laws of pore-fracture structure and seepage characteristics of coal under different confining pressures and cyclic loading amplitudes were analyzed, and the relationship between permeability and effective stress was quantitatively discussed based on sensitivity coefficients. The results show that: under a cyclic loading amplitude of 40% of the peak strength (σ_s), the pore-fracture space of coal samples is compressed, the proportion of meso-macropores in the three coal samples decreases by 12.63%, 28.49%, and 42.91%, respectively, while the P-wave velocity increases; the compression degree is positively correlated with confining pressure. Permeability changes inversely with axial stress and decreases continuously with increasing cycle number, but the decreasing gradient gradually diminishes; with the increase of cyclic loading amplitude (60%σ_s, 70%σ_s), new pores and fractures are generated in coal samples, and the proportion of meso-macropores gradually recovers and rises, with coal sample Y3 showing the highest increase (26.53%), and the P-wave velocity decreases in all samples; the higher the cyclic loading amplitude, the more severe the coal damage, and the larger the P-wave velocity attenuation coefficient and ratio; however, high confining pressure has a certain inhibitory effect on damage, and the degree of P-wave velocity attenuation decreases with increasing confining pressure; in the 60%σ_s and 70%σ_s stages, permeability first decreases and then increases during loading, and first increases, then decreases, and then increases during unloading, showing an overall irreversible downward trend; the permeability stress sensitivity coefficient generally decreases during the loading stage, while it changes relatively gently during the unloading stage, and gradually decreases and tends to stabilize with increasing cycle number; the first cycle has the most significant effect, the sensitivity coefficient during loading is generally higher than that during unloading, with the increase of peak load, the difference in sensitivity coefficients between the two stages becomes smaller.