The invention discloses a drilling-punching integral construction method for a gas extraction drill hole. A drilling-punching integral drill bit is installed at the front end of a drill stem of a drilling machine, the rear end of the drilling machine is connected with a high-low pressure water source converting device through a high pressure sealed water tail, in the hole-drilling construction process, firstly, a low pressure water source is provided for the drilling machine through the high-low pressure water source converting device, variable flow nozzles on the drilling-punching integral drill bit are all open, the slag discharging requirement in the hole-drilling construction process is guaranteed, when hole-drilling construction is ended and punching is started, the drilling machine is not needed to be withdrawn, a high pressure water source is provided for the drilling machine through the high-low pressure water source converting device, meanwhile, the variable flow nozzles in the oblique front direction and the radial direction are closed, only the variable flow nozzles in the direct front direction are reserved for draining water, and hydraulic punching is conducted. According to the method, the integral drill bit is used in the layer-penetrating hole-drilling construction process and the hydraulic punching process, requirements for cooling the drill bit and discharging slag in the low-water-pressure hole-drilling construction process can be satisfied, high-pressure water jet flow can be formed for conducting punching in the high-water-pressure hydraulic punching process, the hydraulic punching process is simplified, and construction efficiency is improved.