Abstract: The main factors affecting the permeability of coal are temperature, hydrostatic pressure and pore pressure, The three parameters of this paper are factors, and the permeability of coal is taken as the research index. Based on the orthogonal test, the permeability of coal under different conditions is tested. The regression analysis is carried out and the distribution of porosity under different pore pressures is studied. Research findings show, The effect of hydrostatic pressure on the permeability of coal is the most remarkable, followed by pore pressure and temperature, and permeability is significantly related to the three parameters; When the pore pressure is greater than 2MPa, the pore pressure has no obvious influence on the permeability of the coal; When the coal temperature is 20 degrees, the hydrostatic pressure is 11MPa and the pore pressure is 3MPa, the permeability of the coal body is the largest, reaching 0.3617mD.