Based on the basic law of the spontaneous combustion of coal，coal spontaneous combustion experiments according to coal from coal-fired body temperature gray GM (1，1) model based on GM (1，1) model was optimized GM (1，1)，and coal fire temperature was predicted. MATLAB mathematical software programming simulation and model accuracy test results showed that optimization of GM (1，1) model with more precision，GM (1，1) model in the prediction of coal temperature higher practical value was optimized，and the outcome had a guiding role in the set of equipment failure diagnosis.