Mine fires are extremely dangerous and destructive. In order to accurately determine the burning state and explosion hazard of the closed fire area, and improve the safe unsealing technology, the law of gas generation and migration in the fire area of Wuyang Mine was systematically simulated. In the study, the CO concentration change law at the fire source, upper corner and return air shaft was obtained; Fluent software was used to simulate the CO concentration distribution in the goaf under 7 different wind speed conditions, and it was found that the farther from the working surface, the higher the CO concentration value, as the wind speed increased, the greater the CO contour of the goaf within a certain range of wind speed sags inside the goaf, and the overall concentration value showed an upward trend.