To investigate the permeability characteristics of coal under different confining pressures and hydraulic loads, SEM micro-scan images and a binary analysis system were used. Based on the fractal characteristics of pore and fracture networks, a model was developed to simulate the porosity and static permeability of the coal rock. Dynamic permeability tests under different water pressures and confining pressures were conducted using a GDS-DYNTTS soft rock rheometer. The research results show that by using reasonable fractal dimensions based on the microstructure images and permeability model, realistic static permeability values can be obtained. Under the coupling of fixed water pressure and different confining pressures, the coal exhibite three different stages of permeability: the stage of pore compression closure, the stage of slow pore deformation release, and the stage of rapid pore deformation recovery. When the confining pressure exceeds 6 MPa, the sensitivity of permeability to water pressure was relatively low. However, when the confining pressure was below 4 MPa, the permeability increase exponentially with increasing water pressure. Under dynamic coupling conditions, the overall trend of coal permeability showed two distinct features: a plateau period and a rapid increase period. The research results provide references for understanding water inflow paths, estimating water quantities in coal seams after mining-induced stress relief, and predicting water inrush risks.