Coal spontaneous combustion in deep mining environments characterized by high geostress, elevated temperatures, and humidity poses escalating risks to mining safety. This study systematically investigates the thermal degradation behavior of coal samples from four Heilongjiang mines (Dongrong No.2, Junde, Longhu, Ronghua No.1) under simulated stratum temperature conditions using thermogravimetric analysis. Experimental results demonstrated that high ground temperature markedly reduces characteristic temperature points and apparent activation energy of coal samples, accelerating the kinetics of oxidation reactions. This study provides theoretical and experimental insights for predicting and mitigating coal spontaneous combustion in deep mines.