In order to determine distribution of spontaneous combustion three-zone in goaf of fully mechanized mining face of a mine, fluent numerical simulation method was used. After determining division standard of spontaneous combustion three-zone in goaf, three belt distribution features and range of Z2304 fully mechanized face were determined. Finally, combining field measurement with numerical simulation, distribution law of spontaneous combustion three-zone in goaf drainage was obtained, which showed that the risk of spontaneous combustion of residual coal existed s and fire prevention measures was necessary to be taken when goaf was normally pushed forward without taking any measures.