Abstract: In order to solve the problems of gas extraction difficulty in outburst coal seam, abnormal gas emission during mining and insufficient utilization rate of gas extraction in bottom pumping roadway, FLAC^3D numerical simulation software is used to simulate the distribution of advance abutment pressure and the development of plastic zone during mining of working face. According to the numerical simulation results, secondary gas extraction in dynamic pressure zone is carried out in bottom pumping roadway. The effect of secondary extraction is evaluated by measuring the volume fraction of gas and measuring the volume of pure gas. The results show that plastic zone in the range of 0-7 m in front of the working face, and the vertical stress plays a major role in destroying the coal body, and the cracks in the coal body are well developed and easy to be extracted. 0-20 m, 20-60 m and 60 m away from the working face can be divided into high efficiency extraction zone, effective extraction zone and original extraction zone, respectively. The volume fraction of gas in each area decreases with the increase of the distance from the working face, and becomes stable until it enters the original rock stress zone. Through the measurement of the volume of pure gas in the dynamic pressure zone, it can be seen that the secondary gas extraction in the dynamic pressure zone of the working face can improve the efficiency of gas extraction and reduce the amount of gas emission.