Abstract: According to the over long period from the open-off cut formation to the coal mining face started to push forward, the slow pushing forward of the coal mi ning face, over high ventilation quantity and the CO density abnormal phenomenon occurred in the goaf of No.1901 Coal Mining Face in Yuanbao Mine, there were four fire prevention and control measures conducted including the ventilation quantity adjustment, the sealing wall established near the top and low corners in the goaf of th e coal mining face, the spraying with the retarder and the nitrogen injection in the goaf.The effect after the measures conducted showed that the first three measures co uld only release CO abnormal phenomenon in the goaf in certain degree, but the nitrogen injection in the goaf could eliminate the spontaneous combustion danger in th e goaf.With the nitrogen injection in the goaf, the analysis on the variation tendency of main gas density showed that the 02 volume fraction reduced from 10% to 6% w ould be the best stage of the nitrogen injection effect. Based on the circumstances, the fire prevention and control conducted could eliminate the spontaneous combustio n danger caused by the slow pushing forward of the coal mining face.