Abstract: According to the characteristics of the coal distribution of thick coal seam，layout the gas station accord with the actual situation，distribution of oxygen in the mined-out area is studied through field observations，take CO concentration as a case studies distribution of dangerous gas in the mined-out area，according to the test face physical model simplified calculation model for numerical simulation，carried out goaf spontaneous combustion dynamic numerical calculation under different working conditions.Studied the influence of key parameters of coal spontaneous combustion is crucial，including changes with time of gas inside the coal spontaneous combustion danger zone seepage velocity distribution and oxygen concentration distribution，high temperature fire point change trend， and preventing coal spontaneous combustion of coal face minimum mining speed， etc