In order to improve the uniformity of air supply in subway ventilation systems and enhance passenger riding comfort and air quality,the CFD simulation software Fluent is adopted to study the characteristics of air-flow organization and the uniformity of air supply in subway air ducts.The results show that under the original structure,local vortices in the ducts are obvious,and the uniformity of air supply is poor.By adjusting the air supply volume of high and low ducts and setting guide plates inside the ducts,the uniformity of the air supply is improved by about 60.4%.Furthermore,the uniformity of the air supply in low ducts is further improved by adjusting the position and size of the guide plates.