The invention provides a method for draining gas of a mining layer of mine, belonging to the technical field of gas drainage of coal measure strata. The method for draining the gas of the mining layer of the mine is characterized in that on the basis of the existing gas drainage technology capable of draining easily or draining the gas of the mining layer, iron insulated electrodes are arranged in perpendicular drill holes and obliquely-intersected drill holes, for the gas drainage of the mining layer; a terminal of an intrinsic safety type pulsed high voltage power supply source is connected with the iron insulated electrodes; the other terminal of the intrinsic safety type pulsed high voltage power supply source is grounded; and according to the gas emission of the mine layer, pulse high voltage electric fields with various powers are applied. According to the method for draining the gas of the mining layer of the mine, the pulsed high voltage electric fields are used for the gas drainage, so that the problem of difficult gas drainage of the mining layer is solved; the action of the pulsed high voltage electric fields can cause the adsorption ability of the gas of the mining layer to be decreased, so that the free gas of a coal body is increased; effective seepage paths for the gas of the coal body of the mining layer can be increased, so that the permeability coefficient of the coal body is increased; and therefore, with the adoption of the drainage method provided by the invention, the gas drainage rate can be improved; and for the mining layer of which the gas is more difficult to drain, the drainage rate can be up to 15% to 30%.