Abstract: Long-term exposure to acid rain and weathering alters the pores and internal structure of open-pile gangue. Different acid erosion and weathering conditions exert a remarkable regulatory effect on the spontaneous combustion tendency of gangue, while the underlying regulatory mechanism remains unclear. To explore the dynamic influence mechanism of acid erosion and weathering on the oxidative spontaneous combustion of gangue, and provide a theoretical basis for the resource utilization and spontaneous combustion prevention of gangue, experiments were conducted using a programmed temperature rise system. Gangue samples were collected from Limin Coal Mine in Inner Mongolia. A series of coupled acid leaching and air-drying tests were designed to simulate acid rain with pH values of 2.5, 3.0 and 3.5. The batch leaching method was adopted for acid erosion treatment over 20 days, with a liquid-solid ratio of 10∶1 (L/kg) and an oscillation frequency of (20±2) r/min. During the experiment, the pH value, electrical conductivity (EC), total dissolved solids (TDS) and oxidation-reduction potential (ORP) of leachate were continuously monitored. Combined with gas chromatography, a programmed temperature rise system (30-405 ℃) was used to comparatively analyze the release characteristics of gases including O₂, CO, CH₄, C₂H₆, C₂H₄ and C₂H₂ from naturally air-dried and oven-dried gangue samples. The oxygen consumption rate and generation characteristics of indicator gases were quantitatively characterized. The results show that after acid leaching of gangue, the pH, EC and TDS of leachate increase, while ORP fluctuates within a certain range. For samples with the same particle size, the gangue treated by stronger acid (lower pH value) presents a greater variation in leachate pH value. As the leaching time increases, metal oxides and mineral components in gangue are gradually dissolved, which may cause pollution to the surrounding ecological environment. Hence, long-term environmental monitoring should be strengthened. The programmed temperature rise tests indicate that naturally air-dried gangue treated with higher acidity consumes significantly more oxygen, and produces larger amounts of CO, CH₄, C₂H₆, C₂H₄ at a faster rate. Meanwhile, the unsaturated hydrocarbon C₂H₂ is generated in advance.