Abstract: In order to study the effect of magnesium salt (magnesium chloride hexahydrate + magnesium hydroxide) on the retarding characteristics of coal spontaneous combustion, the effects of inhibitor dosage and silane coupling agent on the characteristic temperature and thermal effect of coal spontaneous combustion were studied by synchronous thermal analysis and programmed heating-gas chromatography. The results of simultaneous thermal analysis showed that the inhibitory effect was relatively best when the magnesium salt inhibitor was added at 30%, the pyrolysis temperature T₃ was delayed by 40 °C compared with the raw coal sample, and the total heat release was reduced by 165.14 J/mg. F@M_30%·G resisted coal sample adding silane coupling agent mainly delayed the occurrence of coal pyrolysis and ignition, in which the pyrolysis temperature T₃ was 49 °C higher than that of raw coal, and the ignition temperature T₄ was increased by 26 °C. F@M_30% inhibited coal samples can reduce the volume fraction of CO, and the effect of inhibiting spontaneous combustion of coal is gradually enhanced with the increase of temperature. After adding silane coupling agent, the volume fraction of CO of inhibited coal samples can be reduced by about 4×10^-6. The inhibition rate of F@M_30% inhibited coal samples is 30.87%, and that of F@M30%•G inhibited coal samples is as high as 91.57%.