Abstract: The using approach and the recycling technology of return air heat energy of coal mine are studied on the base of inverted conical diffuser. As a result, the extraction device for return air heat energy is optimized. The following achievements and innovations can be obtained based on theoretical analysis, numerical methods and engineering application. Utilizing technology of return air energy is developed based on the inverted conical diffuser of coal mine. Consequently, the return air heat energy used more efficiently and the use of heat energy can be spreaded widely. Based on the feature of day and night temperature difference, the energy storage system that can adapt to the great temperature difference is researched. The energy storage system can conserve heat energy during the daytime and supply heating at night to meet the needs of heat supplying and well-shaft antifreeze. The coal mine return air heat energy based on the inverted conical diffuser is built in a coal mine air shaft and the operation effect of system is verified.