Abstract: According to the practical situation of CO over limit in the goaf of the fully mechanized top-coal caving working face 150201 in Wenzhuang coal mine,the causes of spontaneous combustion of missed coal in the goaf were analyzed,combining with the domestic and foreign research situation of coal spontaneous combustion,the inerting fire-extinguishing method of injecting liquid carbon dioxide was proposed,the techniques and relevant parameters were researched.Field practice shows that liquid carbon dioxide has fast and strong fire-extinguishing capability as well as inerting and explosion suppression effect,and it is one of the most efficient methods for prevention and control of coal spontaneous combustion.