Abstract: The thickness of float coal in Ciyaogou Coal Mine gob is large, which provides material condition for coal spontaneous combustion in gob. In order to prevent fire accidents, we adopt comprehensive measures, including fire preventing and extinguishing by retardant, nitrogen injection, preventability grouting and coal seam water injection, to prevent spontaneous combustion at working face. Through the analysis of tube monitoring system, the CO concentration in the region is less than 10×10^-6 at 10301 working face, and there have been no alarming because of CO concentration out of limit in upper corner, which greatly reduces the fire accidents, and ensures safety mining at working face.