Abstract: The prevention and control of gas in the upper corner of coal mining face has always been emphasized by coal mine safety production. In order to efficiently manage the problem of gas overlimit in the upper corner of the gob, a prevention and control method of applying the mining air multipliers to dilute the gas in the upper corner is proposed. Taking the upper corner of the working face of a U-type ventilation system in a coal mine in Shanxi Province as the research object, using the outlet slit and inlet pressure of the mining air multipliers as the influencing factors, we use Fluent to simulate the characteristics of the local airflow field of the gob and the distribution of gas in the upper corner of the gob under a number of working conditions, and then screen the optimal parameter conditions of the mining air multipliers according to the simulation results for the on-site test, and then combine the results of the test with the simulation of the gas concentration for validation. The results show that the mining air multipliers can increase the wind speed in the return airway, suck the wind flow behind the fan, increase the wind speed in the upper corner, and effectively dilute the gas in the upper corner. The airflow multiplier factor of the mining air multipliers increases with the decrease of the air outlet slit, when the air outlet slit is 1.5 mm, the airflow multiplier factor of 2 m and 5 m in front of the mining air multipliers are 7.84 and 6.84; the inlet air pressure has a smaller impact on airflow multiplier factor, and when the inlet pressure is 0.8 MPa, it has a maximum factor of 7.62 and 7.27; when the air outlet slit is 1.5 mm and the inlet pressure is 0.8 MPa, the gas concentration in the upper corner area can be rapidly reduced to less than 0.1%, which indicates that a smaller air outlet slit and a larger inlet pressure are more favorable to improve the air velocity and dilute the gas in the upper corner, and the former has a greater influence on the gas concentration than the latter. In the field test, the application of mining air multipliers has achieved good results, using the inlet pressure of 0.8 MPa mining air multipliers can reduce the gas concentration in the upper corner to 0.2% within 30 min. The results enrich the theoretical basis for the distribution of the flow field and gas concentration field in the roadway application of the mining air multipliers, and provide theoretical guidance for the further optimization of the local gas control technology of the mining air multipliers.