Abstract: In order to timely grasp the change of gas emission about 40309 working face in Xiaozhuang mine, and eliminate gas danger during mining process, the gas emission data during mining process of 40309 working face are continuously collected in field.What's more, the absolute and relative gas emission amount are analyzed.The relationships between gas emission and daily output, daily mining distance and gas amount discharged by wind are also studied.The results show that from May 25, 2019 to August 14, 2019, the absolute gas emission of 40309 working face decreases with the working face mining, and it is maintained at 21.6-35.4 m³/min.However, the relative gas emission is maintained at 1.58-4.11 m³/t.The average value of absolute gas emission is 26.91 m³/min, with gas emission of coal wall (5.65 m³/min), dropping coal (2.02 m³/min), goaf (2.83 m³/min) and adjacent layer (16.41 m³/min).And the gas from this coal seam accountes for 39.01% of the total emission of the working face, while the gas emission of adjacent layer accountes for 60.99% of the total gas emission.The absolute gas emission of 40309 working face increases with the increase of daily output.And it is increased with daily mining distance and gas discharged by wind slightly, which are not obvious.The relative gas emission of 40309 working face increases with daily output in exponential relationship, increased with the increase of daily mining distance and discharged gas.This study will help prevent and control gas disasters in 40309 working face and provide guidance for the design of similar working face within high gas content.