Abstract: Temperature change is a major character of fiery initiation and development in coal gangue heap. Understanding temperature changing regularity is very useful for prevention and control of fieriness of the coal gangue heap. Based on observation and measurement at several coal gangue heaps with or without fieriness in Pingdingshan Coal Group Corporation, the phenomenon of overall increasing of temperature inside the coal gangue heaps is found. The theoretical explanation and control factors of the phenomenon are given in this paper. To make in-situ monitoring of temperature changes according to this phenomenon will be efficient for prevention of fieriness of the coal gangue heaps.