Abstract: Adopting CFD method, simulation model is used to test and optimize certain metro vehicle air duct uniformity, and reasonable static pressure baffle height, position and size under relatively small air duct resistance are obtained. Study found that using different types of baffle changes air outlet volume at air duct front-end, thus air outlet uniformity is optimized. When baffle height of main duct model is 90 mm, being 30 mm away from outlet edge, air outlet performs good uniformity. For flat duct model with baffle height of 40 mm, being 15 mm away from the outlet edge, considering the impact of air duct flat end tapered section, three back-end baffles of height 40 mm, 30 mm, 20 mm are added respectively, to improve the situation where air outlet is too small in the central position, and is too large at back-end, encouraging uniformity of air outlet in flat air duct.