The invention discloses a method and device for measuring an applied dynamic load axle pressure in a three-dimensional dynamic load gas permeation test. The method comprises the following steps: after the confining pressure and gas pressure of a to-be-tested coal sample reach the required numerical values, utilizing an emitter to send a striking block for striking into the top of an incident bar,thereby generating a dynamic load axle pressure, and then transferring the axle pressure to the coal sample; utilizing a speed meter to measure the speed of the striking block before the striking block strikes into the incident bar and after the striking block is sent by the emitter; and transferring the axle pressure on the coal sample to a transmission rod and an absorbing rod which are provided with strain gages, and receiving the data, thereby detecting the stress and strain conditions of the coal sample. According to the method provided by the invention, the coal sample is supplied with the dynamic load axle pressure by utilizing the emitter to send the striking block for striking into the incident bar; the axle pressure is transferred to the transmission rod and the absorbing rod which are provided with resistance strain gages by the coal sample; the speed of the striking block is detected by the speed meter; and the stress and strain conditions of the coal sample are detected by virtue of the resistance strain gages, thereby supplying the dynamic load axle pressure to the coal sample and performing the detection.