In order to reduce the impact of high temperature thermal hazards in deep mines, paraffin-autoclaved aerated concrete composite phase change material (AAC-PCM), was developed for mining applications and mixed into the tailing sand backfill in different masses to make autoclaved aerated concrete phase change thermal storage backfill. Investigate the strength characteristics and thermal properties of the thermal storage backfill, mechanical tests, thermal conductivity tests, SEM and DSC tests were carried out on the backfill mixed with different resulting in a gradual decrease in the strength of the composite thermal storage backfill with the addition of AAC-PCM, but the decrease in strength gradually decreases. The maximum reduction in thermal conductivity was 30% and the specific heat capacity increased by about 31.4%. Doping a small amount of AAC-PCM can significantly improve the thermal storage capacity of the backfill and has good strength for practical use in mines.