Abstract: Deep-hole broken roof blasting is an effective method to deal with the rock burst of hard roof, but a large amount of harmful gases are generated after the blasting such as high concentration of CO, which not only seriously affects the downhole air current environment, but also interferes with the prediction of internal fires in coal mines. Based on previous research results, through theoretical calculations and statistical analysis on-site measurement, it is found that 75% of the CO gas generated by the blasting will be discharged into the airflow of the working surface within 1 h and discharged with the airflow after deep-hole broken-top blasting. The remaining 15% will be accumulated or adsorbed in the fractured coal rock body, and will be gradually discharged in 7-9 days with the gas pre-pumping.