Abstract: The accurate prediction of the degree of coal spontaneous combustion is the key to the prevention and control of coal seam spontaneous combustion.A relatively single early warning index and simple early warning method cannot accurately determine the stage of coal spontaneous combustion in goaf.In order to further improve the reliability of coal spontaneous combustion early warning,taking Kongzhuang Coal Mine as a research object,a programmed temperature coal spontaneous combustion experiment is conducted to explore the relationship between gas concentration variation law and temperature during the coal spontaneous combustion process in this mine.The initial concentrations of various characteristic gases during the coal oxidation and heating process are measured.According to the occurrence laws of CO,C₂H₆,C₂H₄,C₂H₂ and the variation laws in CO/O₂,CO/CO₂,C₂H₄/C₂H₆,five characteristic temperatures are determined,and the coal spontaneous combustion process is divided into six stages such as safe period,oxidation period,heating period,thermal decomposition period,fission period,and combustion period.A grading early warning index system for coal spontaneous combustion in the 7436 working face of Kongzhuang Coal Mine is proposed.The application of this grading early warning system successfully predicts the degree of coal spontaneous combustion in the goaf of the 7436 working face,and ensures the safe stoping of this working face by taking timely nitrogen injection and grouting measures.