Abstract: According to the distribution of loose coal in the gates of fully mechanized longwall top coal caving face,some sub zones are divided.The mathematic model of coal spontaneous combustion is deduced.And the method of accounting the main parameters in above model is put forward.The method is used in the tailgate of workface 4308 in Dongtan Coal Mine for predicting spontaneous of loose coal.The results show that the accuracy of predicting spontaneous combustion of loose coal in the gates is already over 90%.