Abstract: The intensity of air leakage not only increases the risk of spontaneous combustion of coal, but also is the cause of coal fire disasters caused by spontaneous combustion of coal left in the goaf. Aim to find the influence of the air leakage intensity on the spontaneous combustion characteristics of the remaining coal when the fire zone is opened, the coal spontaneous combustion characteristics measuring device is used to conduct a temperature-programming experiment on the coal samples, and then Fourier transform infrared spectroscopy（ＦＴＩＲ） is used for analysis to obtain different gas environments. The relative content of functional groups changes at each characteristic temperature point. The results show that in the oxygen-containing groups, the content of -COOH increases as the temperature rises. Although the change range of -C-O- is not obvious with the rise of the temperature point, its content is relatively high; in the functional groups of -OH, it is present at all temperature stages. It exists and the peak intensity is obvious; among the aliphatic hydrocarbons, the peak areas of -CH₃ and -CH₂ are both large, and both dry air and nitrogen atmosphere participate in the reaction at various temperature points, and the activity is high. Through structural parameter value analysis, T₁₂₀ is the key active point temperature. In the coal sample that is naturally cooled under dry air or nitrogen atmosphere, the functional groups of the raw coal react more violently in T120, and the functional groups change more. As a whole, the increasing and decreasing trend of functional group changes in nitrogen atmosphere is smaller than that in dry air atmosphere, and the risk of coal re-ignition is also reduced.