As for the main coal reservoirs of the lower Permian Shanxi Formation in the central-southern Qinshui basin, the permeability gradient of coal reservoirs tends to increase in exponential fanction and the pressure gradient to rise in logarithmic function with the increase of the principal stress difference σ1-σ3 of modern tectonic stress field, which is predominantly controlled by the correlation between the main stress direction and the preferentially developed direction of natural fissures in coal reservoi...