Abstract: The article uses the method of experimental simulation, simulates the change of mechanical properties and air permeability and gas desorption speed under different moisture of coal. The results show that with the increase of moisture, the compressive strength and air permeability and gas desorption speed of the coal have been declined when the coal moisture is less than 6%～8%; the relationship of absolute variation and relative variation of the coal parameters is R＞permeability K＞cumulative gas desorption amount Q_{150 min}; the compressive strength of the coal is the major controlling factor to evaluate the effect of coal seam infusion anti-outburst; the air permeability and gas desorption speed of the coal are auxiliary parameters; the coal parameters don’t change significantly after the coal moisture is greater than 6%~8%.