Abstract: With increasing depth of mining and gas drainage intensity, nonflammable coal is very likely to develop into spontaneous combustion under a dual role of the advance oxidation and secondary oxidation. Based on the coal-oxygen complex role theory, dialectical analysis and field measurement verification, this paper divided the coal seam spontaneous combustion danger zone of 6₁35 Y-type ventilation mechanized mining face of Qidong Coal Mine as follows: the spontaneous combustion hazard of the 6₁35 machine alley protection pillar is serious harm; the 6₁37 drainage roadway overlying 6₀ coal followed, and the spontaneous combustion hazard of 6₀ coal covered the goaf near the 6₁35 wind lane is not obvious harm.