Abstract: In order to study the influential effect of gas environment on coal surface potential under the uniaxial loading condition, we build the coal uniaxial compression failure observation monitoring system under the nitrogen confining pressure, the surface potential of coal under different confining pressure was tested; the influence mechanism of coal loading and gas on the potential was discussed. The experimental results show that the coal in confining pressure loading can produce the surface potential signal, and the potential signal and the changes of stress and gas pressure have a certain relevance; for the same type of coal, with the increase of filling nitrogen pressure, the stress of coal structure changes. The fluctuation range of potential signal increases about 0.2 mV, the amplitude of the mutation is obvious, and the potential difference increases from 0 mV to 2 mV before the coal main rupture occurs. When the main fracture occurs, the potential signal increases obviously.