Abstract: To study spontaneous combustion characteristics of pulverized coal under the condition of lean oxygen, we use TG/DSC and FTIR spectrometry to test the combustion heat release process of Gubei gas coal samples under different oxygen concentration. We analyze temperature point characteristics, TG and DSC curves under the lean oxygen condition. The change laws of the release of CO and CO₂ in infrared spectrum is studied. By the integral method, we calculate the activation energy change laws of active temperature point to the point of ignition. Research shows that coal and oxygen reaction can still continue under the condition of lean oxygen. The characteristic temperature points increase in the high temperature oxidation stage. DSC, TG curves offset to high temperature zone, and the peak temperature of CO and CO₂ is increased. Weight gain stage to the combustion phase of the activation energy changes little.