Abstract: In order to explore the influence of airflow velocity on the exhaust time of blasting fume in deep open-pit mine, the unsteady numerical model of deep open-pit mine was constructed by using CFD numerical simulation method.The diffusion process of blasting fume were simulated under the conditions of airflow velocity of 3 m/s, 6 m/s, 9 m/s, 15 m/s and different blasting locations. The influences of airflow velocity on the characteristics of airflow and the exhaust time of blasting fume were investigated. The results show that the airflow structure in the open-pit mine are changed from single recombination circulations to double recombination circulations as the airflow velocity increases under different blasting locations; when the airflow velocity is greater than 6 m/s, the declining range of exhaust time gradually decreases with the increase of airflow velocity, and the influence of airflow velocity on exhaust time gradually decreases; the exhaust time of blasting fume in open-pit mine decreases gradually as the airflow velocity increases and the exhaust time of blasting fume followed exponential function with the airflow velocity under different blasting locations.