Abstract: Xinjiang is rich in coal resources, but with the increase of mining intensity, the number of composite goafs in many regions is increasing, and the amount of gas gushing from the working face also increases due to the secondary pressure of the mining overburden, which causes a large number of associated disasters, which increases the difficulty of the mining work. In order to solve the problem of gas treatment in high gas and thick mining compound goaf, combined with the spontaneous combustion characteristics and gas occurrence characteristics of 9-15 coal seam coal in Sulfur Gully Coal Mine, the 9-15 coal seam composite goaf was studied, and the real-time observation was carried out by using the change law of gas extraction concentration, high drilling site and working face advancement of each high borehole in the 12号 high drilling site along the track of the working face, and finally the dynamic change law of gas extraction concentration after the 9-1508 working face entered the composite goaf was obtained,effectively solve the problem of gas control in composite goaf.