The main bridge of Shuangliu Yangtze River Bridge on the Xingang Expressway in Wuhan City is a single-span suspension bridge with a main span of 1 430 m and a bridge tower of 272.75 m. The stiffening girder is in the form of a closed flat steel box girder with a width of 50.5 m. In order to study the wind-resistant performance of the bridge during operation, the performance of vortex-induced vibration of the girder was tested through wind tunnel tests of section model with two different geometric scales of 1∶60 and 1∶30, respectively. The sensitivity of the vortex-induced vibration response to the structural damping ratio was analyzed, and the effect of installing a guide vane inside or on both sides of the maintenance rail on the performance of vortex-induced vibration was evaluated. The flutter performance of the bridge was tested in a wind tunnel by using the 1∶60 geometrically scaled section model, in which the effect of the guide vanes on the flutter performance was analyzed. Finally, the flutter performance of the bridge was tested through wind tunnel tests of the full-bridge aeroelastic model with a scale ratio of 1∶205. The results show that the bridge shows good flutter performance under the wind angle of attack from ?3° to +3°, and the critical flutter wind speed at each angle of attack is more than 20% higher than the tested flutter wind speed. The vortex-induced vibration response is significantly affected by the structural damping ratio. When the vertical bending and torsional damping ratios are 0.136% and 0.048% respectively, significant vertical and torsional vortex phenomena were observed in the large-scale wind tunnel test of the section model. However, if the former damping ratios are increased to 0.217% and 0.164%, respectively, the vertical vortex-induced vibration and torsional vortex-induced vibration almost disappear. Installing the guide vane on the maintenance rail can suppress the vortex-induced vibration under a small structural damping ratio, and has little influence on the flutter performance of the bridge.