Taking the 21215 working face of Dongpang Mine as the research object, under the conditions of stable air distribution of the working face at about 1750 m3/min, high-level drilling drainage and corner intubation drainage, the gas and air volume of the working face were measured by unit method, and the air leakage distribution and gas distribution in the goaf of the working face were obtained under the two different conditions of upper corner bag plugging and open treatment, which provided theoretical support for gas prevention and control of U-type ventilation working face under drainage conditions.