Abstract: In order to investigate the link between the microscopic groups of coal and the exothermic characteristics of coal during spontaneous combustion, the thermal parameters and microscopic groups of coal samples with different degrees of metamorphism were investigated by differential scanning calorimetry and infrared spectroscopy during the spontaneous combustion of coal. The results show that the content of aromatic hydrocarbon compounds in weakly caking coal, fat coal, coking coal and anthracite gradually increases with the increasing degrees of metamorphism, at 33.7%, 39.8%, 47.5% and 65.4%, respectively, while the content of oxygen-containing functional groups gradually decreases, at 53.2%, 50.5%, 43.6% and 24.6%, respectively. A Gaussian mixing model was used to determine the ignition point temperature of the coal during exothermic process. The results indicate that coal with high degree of metamorphism have higher ignition point and lower risk of spontaneous combustion. More recently, the relationship between coal ignition point and microscopic groups was determined by using Pearson correlation coefficient method. The results indicate that coals containing more substituted benzene, -C=C-, and -CH₃ will have a higher ignition point temperature and a reduced risk of spontaneous combustion, while the opposite is true for coals containing more -CH₂ and -COOH.