Abstract: Through reaction dynamics theory analysis and measurmentof indicators gas of the three coal samples,the activation energy values that coal samplesneed to generate indicator gases CO,CO₂,and CH₄ is calculated;the relation between the activation energy values and coal rank,volatile matter,spontaneous combustion tendency is analysed.The research indicates the activation energy that coal need to generate CO increases with the increase of coal rank and decreased with increasing of volatile,which is consistent with the spontaneous combustion tendency.Activation energy that coal need to generate CO can be used to judge the spontaneous combustion tendency more accurately.The research resultshas important application value and significance for getting gas to determine the state of coal in coal mine and the prevention and control of the mine fire.