Abstract: The hard and thick roof slabs are usually controlled by deep hole roof breaking blasting to relieve pressure and prevent rock burst. After blasting, the CO gas exceeding the limit interferes with the prediction of coal seam spontaneous combustion. To reduce the impact of harmful gas CO from blasting on determining coal spontaneous combustion, through laboratory experiments to analyze the main harmful gases produced by emulsion explosives used in Kuangou Coal Mine. Analyzing and elucidating the CO gas diffusion mechanism after blasting based on on-site CO sensor monitoring data. On site testing uses discharge system to discharge CO gas from the blasting hole. Based on on-site monitoring data, investigate the effectiveness of the drainage system, optimize the parameters of the drainage system, and determine the optimal drainage flow rate and roadway air supply volume. The research results indicate that the Kuangou Coal Mine emulsion explosives after the explosion, the main harmful gas is CO; After blasting, CO gas mainly gushes out from the blasting hole and forms a smoke cluster in the roadway, the CO gas volume fraction occur to sharp change in the monitoring data. The CO gas slowly released through blasting holes, coal rock fractures, and coal detachment. In addition, the CO gas accumulation or adsorption in the goaf, as well as ventilation and other factors, result in CO gas volume fraction sharp change and slowly decreasing; The drainage system can maximum shorten the return air CO gas overrun time by up to 38 minutes, and maximum reduce the return air CO gas volume fraction peak by 45%; Under different conditions of roadway air supply volume and drainage system flow rate, the drainage effect is better when air supply 1400m3/min and drainage flow 50m3/min; Increasing the tunnel air supply volume can accelerate the blasting fume migration rate and shorten CO gas overrun time, but it will also have a certain impact on the drainage system gas collection port.