Abstract: To effectively eliminate the hidden dangers of natural fire in mine goaf, the research on composite inert gas fire prevention technology is carried out in view of the shortage of single inert gas fire prevention technology in existing mines. Combined with the mechanism of N₂ and CO₂ fire prevention and its characteristics analysis, a composite inert gas fire prevention system with ground fixed N₂ and CO₂ coupled gas coupled perfusion is proposed. Through the practice of fire prevention engineering of S2905 working face of Daxing Mine, the composite inert gas fire prevention technology can quickly and effectively reduce the parameters such as ambient temperature, oxygen and the concentration of the gas maker in the hidden danger area, and ensure the safe and efficient mining of the mine.