Abstract: The indicative gas distribution and migration law of flowing gas in the spontaneous combustion zone are obtained by monitoring the beam pipe in goaf. On this basis, the 3 D mathematical model of the gas migration in goaf is designed, which determines the oxygen concentration distribution and hazardous area range of spontaneous combustion.At the same time, using radon detection technology to verify the abnormal area on the ground surface, forming a“Trinity”prediction system of spontaneous combustion area in goaf composed of underground monitoring, computer simulation and surface verification.This method is applied to the 1293 working face of Huangbaici Mine.The result shows, in the current ventilation and mining schedule, the oxygen distribution is irregular “O”area, and the coal spontaneous combustion zone (oxygen concentration 10%-15%) presents“U”type distribution in the distance from the intake airway 100-450 m, return airway 70-250 m, the middle distance from the working face 50-140 m.The research provides a new theoretical guidance for the accurate detection of spontaneous combustion area in goaf.