It is imperative to have an in-depth understanding of the chemical inhibition mechanism for spontaneous combustion of coal, not only for controlling and preventing spontaneous combustion of coal in the coal mining industry but also for reducing emissions of hazardous gases. N,N-dibenzylhydroxylamine (DBHA) as a hydroxylamine free radical scavenger can be chosen as a feasible stabilizer for the spontaneous combustion of coal. In this study, the inhibitory performance of DBHA was examined by investigating coal mass changes and heat release obtained from thermogravimetric and differential scanning calorimetry. The effect of DBHA on change of the active groups during coal oxidation at different temperatures was determined by in situ Fourier-transform infrared spectroscopy. Density functional theory was also introduced to optimize the active radical model and calculate thermodynamic parameters. Experimental results showed that DBHA exerted a strong inhibitory effect on the spontaneous combustion of coal, especially for lignite and sub-bituminous coal. DBHA can combine with a hydroperoxide intermediate to form a stable compound, causing the effect of reducing the free hydroxyl content in coal and interrupting the formation of aldehydes and carboxylic acids. Additionally, it can combine with alkyl radicals to form stable compounds. DBHA exhibits an inhibitory effect by increasing the activation energy at each stage, especially during the accelerated oxidation and quick oxidation stages. Furthermore, the possible reaction paths between free radicals and DBHA were also proposed on the basis of the experimental findings.