Abstract: In order to optimize the application effect of the “two inlet one return” ventilation system, reduce the risk of spontaneous combustion of coal remaining in the goaf, based on theoretical analysis combined with COMSOL numerical simulation software, relying on north 1103 working face engineering background of Weijiadi Coal Mine, aim at the different layout positions of the second air inlet lane, the air volume ratio of the two air inlet lanes, the width of the air inlet side blocking wall and the advance distance of the working face, research has been carried out to analyze the oxygen volume fraction and oxidation zone range of the goaf under different working conditions. The results show that the position of the second air inlet roadway has a great influence on the oxidation zone range of the goaf. When the ventilation and prevention roadway is located at 0.618D on the right side of the air inlet roadway, the maximum width of the oxidation zone is 23 m; by changing the air volume ratio of the two air inlet tunnels, the oxygen affected area can be reduced and the oxidation zone range of the goaf can be changed; the existence of sealing wall on one side of air inlet roadway can inhibit air leakage in goaf to a certain extent, but there is an optimal sealing range; with the advance of the working face, the scope of the oxidation zone in the goaf tends to be stable after 120 m.