Abstract: In order to study the transformation law of active functional groups in the low-temperature oxidation process of coal gangue spontaneous combustion and its relationship with gas release, the experimental system composed of Fourier transform infrared spectrometer and programmed temperature control device was used to analyze the spectral experimental data of coal gangue samples at 30-350 °C in air atmosphere. The Spearman method was used to study the correlation between gas release and functional groups. The results showed that the content of hydroxyl groups in the spontaneous combustion process showed an overall upward trend, the content of aliphatic hydrocarbons in the oxidation reaction was high and the reaction was active, and the oxygen-containing functional groups were affected by aliphatic hydrocarbons in the oxidation. The amount of CH₄ gas released increases with the increase of aliphatic hydrocarbon −CH₂−, substituted aromatic hydrocarbon C−H and hydroxyl content. CO gas increases with the increase of carbonyl and aromatic hydrocarbon C−H content, and decreases with the increase of oxygen-containing functional group content. The release of CO₂ gas during oxidation mainly increases with the increase of hydroxyl and carbonyl content, showing a very high correlation.