There are great hidden dangers of spontaneous combustion in top coal caving mining in positive pressure ventilated mine. Combining with the actual situation of top coal caving face in 12 coal composite area of Huojitu Well, this paper studies the risk factors of spontaneous combustion and the prediction and prediction system to ensure safe mining in close distance coal seam group of positive pressure ventilated mine. Based on the actual situation in the field, distributed measurement of goaf temperature is achieved by bundle tube extraction gas test system combined with other gas detection means, and distributed optical temperature measurement system, which improves the reliability and accuracy of monitoring results, and provides reference for prediction and prediction of goaf spontaneous combustion under the same conditions.