Abstract: For the problem that CO anomaly occurred in 22307 goaf at the initial stage of 22308 coal mining face in Bulianta Coal Mine, the results did not meet expectations after taking comprehensive treatment measures in 22307 goaf, which includes liquid CO₂, liquid N₂ injection and grouting. There are open flame and smoking in surface mining pit corresponding to 22308 coal mining face, through searching surface cracks, and there are air leak channel among surface mining pit, 12 coal mining area and 22307 goaf with SF₆ marked gas. CO content was dropped sharply in 22307 goaf through taking some measures for the mining pit like excavating, loess overburden and compaction, this confirmed that spontaneous combustion of coal gangue in mining pit was the fundamental reason leading to CO abnormal occurred in 22307 goaf.