Abstract: In order to obtain the influence laws on permeability and distribution characteristics of water pressure in coal seam during water injection, the permeabilit y of three different coal samples was tested under different water injection pressure, the water pressure distribution characteristics was simulated under the water inject ion pressure of 3, 5, and 8 MPa.The results showed that the permeability of coal samples gradually increased with injection pressure increasing and meet a cubic polyn omial variation.The range of water pressure in coal seam was "口" distribution, water pressure gradually decreased with the distance to the hole wall increasing under th e constant water injection pressure, the flow velocity also reduced.The water pressure gradient and the effective range gradually increased with injection pressure incre asing, the water pressure gradient gradually decreased with the distance to the hole wall increasing, the radius of the maximum water pressure range was about 9 m.