In order to effectively divide the ' three zones ' of spontaneous combustion in goaf of low gas fully-mechanized mining face, the CO concentration in goaf is used as the division index. Based on the fact that the increase of CO concentration from the corner to a certain point on the air inlet or return side of goaf is K times of the maximum increase
（from the corner）, K can be taken as 20 % -40 %. A horizontal line is made at this point and intersects with the CO concentration curve at K1 ( near the working face ) and K2 ( near the deep part of goaf ). The left area of K1 is the heat dissipation zone, the area between K1 and K2 is the oxidation zone, and the right area of K2 is the suffocation zone. Taking 2203 working face of Dabaodang Coal Mine as an example, field measurement was carried out. The results show that the width of the heat dissipation zone on the air inlet side of the 2203 working face is 69.53 m, and the width of the oxidation zone is 165.19 m. The width of the heat dissipation zone on the return air side is 21.96 m, and the width of the oxidation zone is 174.23 m. The range of the spontaneous combustion ' three zones ' in the goaf of the low gas fully mechanized mining face is divided by the CO concentration to provide a basis for mine fire prevention and control.