Abstract: Taking a fully mechanized mining face of a mine in Shaanxi Province as an example, in order to study the law of “three zones” of spontaneous ignition in goaf of coal mine, gas data were collected and oxygen distribution law was analyzed by laying beam tube combined with field observation.The “three zones” model of goaf was constructed based on FLUENT software, and the range of “three zones” of goaf was divided with O₂ concentration as the dividing index, and the maximum distance of oxidation heating zone was determined.The simulation results are compared with the field gas data, combined with the shortest spontaneous ignition period of floating coal.The oxidation zone in the goaf of the mine is 61 meters to 190 meters away from the working face, the return air side is 46.5 meters to 154 meters away from the working face, and the maximum oxidation zone width is 125.6 meters.The maximum safe driving speed is 5.6 meters per day.