The determination of the original gas pressure of the coal seam is of great significance to the mine gas management, and the traditional passive pressure measurement method has the characteristic of taking a long time. In order to quickly determine the coal seam gas pressure of Wuyang Mine 7801 face, the active gas pressure measurement technology was proposed, the principle of active gas pressure measurement technology was clarified, and the choice of compensation gas was analyzed, which showed that the compensation gas can be N2. 2 pressure boreholes constructed at the site for gas pressure measurement, and the pressure of the injected compensation gas was 0.5 times of the expected gas pressure, 2 boreholes, the results were 0.25 MPa and 0.28 MPa respectively; meanwhile, the coal samples were selected to test the coal seam gas content and adsorption constant and other parameters in the laboratory, and the coal seam gas pressure was calculated backwards based on Langmuir's equation to verify the on-site measurement results to determine the velocity of gas pressure.