The permeability test of coal in the complete stress-strain process is carried on the MTS815 Servo-controlled Rock Mechanical Test System. Test results indicate that the permeability rate curve and the complete stress-strain curve of coal almost have the same variation trend. But the permeability rate-strain curve is relatively “hysteretic” which indicates that the close relativity between the evolvement of damage and the development of permeability rate and the permeability developing needs a time. The micro-structure and micro-composition of coal are more complicated and different than other sedimentary rocks; so the permeability of different kinds of coal is much different. Moreover

the micro-porosity and micro-fracture of coal are more developed

so the influence of available confining pressure on penetrability of coal is more obviously.