Abstract: This paper studied the effect of acoustic wave on the characteristics of coal reservoir permeability by a self-explored testing system of methane seepage under acoustic wave.The results show that without the influence of acoustic wave, the permeability of coal firstly decreased and then increased with the increase of the ratio of effective stress and effective volume-stress.The permeability of coal rapidly decreased at the beginning and then remained stable, eventually increased.The permeability of coal decreased, kept stability with the increase of effective volume-stress when the ratio of effective stress kept steady in value.The permeability of coal under acoustic wave was greater than that without acoustic wave.The permeability of coal increased firstly and then kept stability with the increase of acoustic wave treatment time.Meanwhile, the permeability of coal increased with the increase of acoustic intensity, and the ratio of permeability between with acoustic wave and without acoustic wave showed a linear relationship.In the same conditions, the acoustic field could promote methane diffusion and migration.The shorter the distance was from ultrasound sources, the better the effect of improving the permeability of methane was.The relationship between the increment of methane flow and the distance to ultrasound sources was negative exponential function due to the attenuation of acoustic wave propagation in coal seam and the acoustic energy decreased.This study enriches the theory of the effective extraction of coal bed gas by acoustic wave.