As a typical solid waste, coal gangue is highly susceptible to spontaneous combustion. Conventionally, method for controlling spontaneous combustion of coal gangue is to inhibit the oxidation and self-heating of gangue by utilizing soil covering to isolate the gangue from oxygen. Using various methods, such as FTIR, TG/DSC, program heating and physical simulation, the change of spontaneous combustion characteristics (SCCs) of coal gangue under 3-21.0% O-2 was explored. Results show that lean-oxygen significantly decrease the heat release from coal gangue during lowtemperature oxidation, inhibit the generation of O-containing functional groups, and postpone the appearance of characteristic temperature points on the thermogravimetry (TG) curve. Between 30 and 140 degrees C, the activation energy during oxidation of coal gangue ranges 29.85-47.72 KJ/mol. The oxygen consumption rate (OCR) of coal gangue showed a nonlinear positive correlation with O-2 concentration. Field simulation test showed that after coal gangue was stacked for 60 d, the gangue temperature rose to 39.6 degrees C. After covering the soil, the temperature data increased slowly. However, oxidation of coal gangue was not completely inhibited even the lowest O2 concentration reduced to 18.35%. In conclusion, investigation in the paper provides further guidance for reducing risk of gangue self-ignition.