Abstract: Through numerical simulation and field investigation, the protection effect of lower protective layer of Guqiao Coal Mine is verified. Lower protective layer of Guqiao Coal Mine 11-2 coal seam is mined with pressure relief gas drainage in 13-1 bottom drainage roadway. If the gas extraction rate is above 60%, the expansion deformation rate of the protected coal seam is increased to more than 5‰ in the protected area under protection. The residual gas content, the residual gas pressure, the calculated gas pressure, the coal sample strength coefficient, the gas dispersion index and the comprehensive index are not exceeded, the outburst danger of the protected area in 13-1 coal seam is eliminated and vertical protection is realized. It is obtained from numerical simulation that the protected coal seam is affected by the mining effect. The mining influence line of the location of the cut hole is extended to the outer side 50 m, and the mining influence line of the working face is extended to the outer 100 m.