Abstract: In order to research distribution laws of carbon monoxide in mine goaf, a certain mine is taken as an example to build the computational fluid mechanics model, and monitoring points are laid out in working face, powered support and return air roadway in different hight. The software of Fluent is used to simulate the concentration percentage of carbon monoxide at different monitoring points. The results show that carbon monoxide trends to the side of return air roadway in the goaf near the working face, and the concentration of carbon monoxide increases gradually from the intake air roadway to the return air roadway, and achieves the maximum in the upper corner place. The upper corner and return air roadway are the places where the concentration of carbon monoxide is much higher than any other areas in the whole mine. In the vertical direction, concentration of carbon monoxide is in a linear relationship with the height, but the overall concentration changes a little. The buoyancy produced in the upper corner makes the wind into rotating forms, which causes the accumulation of carbon monoxide in the upper corner.