This study investigates the thermodynamic characteristics and kinetic mechanisms of bituminous coal in low-oxygen environments using thermogravimetry (TG) and differential thermogravimetry (DTG). Three coal samples from different regions were tested under varying oxygen concentrations (5–21 vol.%). The results show that as oxygen concentration decreases, the combined combustion index of the coal samples also decreases during the oxygen-absorption stage. The apparent activation energy of coal increases with conversion rate (temperature), and the reaction mechanism shifts from three-dimensional dissipation to two-dimensional as oxygen concentration decreases. During pyrolysis combustion, activation energy initially rises and then decreases with increasing conversion, with a short phase of increased activation energy at lower oxygen concentrations. The kinetic mechanism transitions from stochastic nucleation and growth to one-dimensional phase-boundary mode with decreasing oxygen concentration. These findings enhance understanding of coal oxidation combustion in low-oxygen environments, contributing to strategies for mitigating coal spontaneous combustion. The study highlights the importance of oxygen concentration in combustion dynamics, showing that low-oxygen environments inhibit low-temperature exothermic oxidation. Previous research has focused on oxygen-enriched conditions, but this study emphasizes the role of oxygen concentration in coal spontaneous combustion. The research aimed to elucidate the impact of oxygen concentration on spontaneous coal combustion processes, the relationship with apparent activation energy, and the modulation of kinetic modes based on oxygen concentration. These findings contribute to a deeper understanding of coal spontaneous combustion phenomena and inform improved fire management strategies. The study used three coal samples from different regions, with proximate analytical results detailed in Table 1. Each sample weighed 10 ± 0.3 mg, and the air supply rate was maintained at 100 mL/min. A low-oxygen environment was defined as an environment where the oxygen concentration is lower than that in the air, specifically, conditions where the oxygen volume fraction is less than 21 vol.%. The experimental setup consisted of a mixture of nitrogen and oxygen, with oxygen concentrations ranging from 5 to 21 vol.%. The oxygen concentration of the mixture was set at 21 vol.% to simulate atmospheric conditions.This study investigates the thermodynamic characteristics and kinetic mechanisms of bituminous coal in low-oxygen environments using thermogravimetry (TG) and differential thermogravimetry (DTG). Three coal samples from different regions were tested under varying oxygen concentrations (5–21 vol.%). The results show that as oxygen concentration decreases, the combined combustion index of the coal samples also decreases during the oxygen-absorption stage. The apparent activation energy of coal increases with conversion rate (temperature), and the reaction mechanism shifts from three-dimensional dissipation to two-dimensional as oxygen concentration decreases. During pyrolysis combustion, activation energy initially rises and then decreases with increasing conversion, with a short phase of increased activation energy at lower oxygen concentrations. The kinetic mechanism transitions from stochastic nucleation and growth to one-dimensional phase-boundary mode with decreasing oxygen concentration. These findings enhance understanding of coal oxidation combustion in low-oxygen environments, contributing to strategies for mitigating coal spontaneous combustion. The study highlights the importance of oxygen concentration in combustion dynamics, showing that low-oxygen environments inhibit low-temperature exothermic oxidation. Previous research has focused on oxygen-enriched conditions, but this study emphasizes the role of oxygen concentration in coal spontaneous combustion. The research aimed to elucidate the impact of oxygen concentration on spontaneous coal combustion processes, the relationship with apparent activation energy, and the modulation of kinetic modes based on oxygen concentration. These findings contribute to a deeper understanding of coal spontaneous combustion phenomena and inform improved fire management strategies. The study used three coal samples from different regions, with proximate analytical results detailed in Table 1. Each sample weighed 10 ± 0.3 mg, and the air supply rate was maintained at 100 mL/min. A low-oxygen environment was defined as an environment where the oxygen concentration is lower than that in the air, specifically, conditions where the oxygen volume fraction is less than 21 vol.%. The experimental setup consisted of a mixture of nitrogen and oxygen, with oxygen concentrations ranging from 5 to 21 vol.%. The oxygen concentration of the mixture was set at 21 vol.% to simulate atmospheric conditions.