The invention discloses a full air pressure air borrowing method for a coal mine underground tunneling roadway, which adopts the following technical scheme: in the process of coal mine roadway tunneling, a local fan is required to supply air for the tunneling roadway, and shutdown of the local fan due to fault easily causes gas accumulation; a local ventilating device in the tunneling roadway adopts a fan installed in an air inlet roadway to extend to a fan drum in the tunneling roadway to supply air for the tunneling roadway; the last air in the roadway is led out by negative pressure of a main mine ventilator. In the method, an air borrowing door is built in the roadway on the position of the full air pressure at the air inlet side of the tunneling roadway and is provided with a shutterand a fan drum opening with a baffle; the fan drum opening is communicated with an air supply drum in the tunneling roadway by tee joint; Under normal conditions, the shutter is rolled up and the baffle of the fan drum opening is closed to keep normal ventilation of the roadway; when the local fan shuts down, the baffle of the fan drum opening is opened, the roller shades of the shutter are put down and the mine ventilation negative pressure is adopted to supply air for the tunneling roadway to prevent gas accumulation so as to realize the purpose of secure production.