Abstract: To solve the problems of gas overrun at the upper corner in full mechanized mining face and spontaneous combustion in the goaf of Zhengbang coal mine, the horizon position of high level gas drainage gateway was analyzed from aspects of gas controlling, spontaneous combustion and gas flow field. It was found that the best horizon position of high level gas drainage gateway was K2 limestone floor, which could not only reduce stopping effect of gas transportation by limestone, but also exert a better extraction effect of high level gas drainage gateway. Furthermore, this floor could ensure the stability of the three-horizontal zones in the goaf, and effectively prevent its spontaneous combustion. The optimized horizon position of high level gas drainage gateway was verified by measured data.