Abstract: Based on an orthogonal test design, and taking a tunnel in Wuhan City as the study subject, this paper uses the FDS numerical simulation software to study the influence induced by the change of air curtain parameters on the smoke prevention effect during tunnel fire, determines the significant degree of each factor to smoke prevention effect by range analysis and variance analysis, eventually obtains the optimal combination of air curtain parameters. The results show that: the installation of air curtains in the tunnel has a significant smoke control effect, of which jet width has the greatest impact on the ambient temperature and visibility for the evacuation of tunnel personnel, followed by the jet angle; the jet width has the greatest impact on the smoke prevention efficiency of the air curtain while the jet velocity comes second. Through a comprehensive analysis of the three characteristic indicators, i.e. evacuation ambient temperature, visibility, air curtain smoke prevention efficiency, this paper finds that when the firepower is 20 MW, the optimal combination of the tunnel air curtain is jet speed of 30 m/s, jet angle of 20°, jet width of 0.4 m, and air curtain spacing of 60 m. With the adoption of the optimized solution, the ambient temperature for tunnel evacuation is lower than 60 ℃, while the visibility is higher than 20 m, and the smoke prevention efficiency is as high as 97%, meeting the requirements for personnel evacuation in case of fire.