Abstract To suppress the vortex-induced vibration (VIV) of long-span bridges, an active flow control method, i.e. the external suction-blowing method (ESBM), is proposed in this study based on the efficiency of the three-dimensional spanwise-varying flow control method and the suction/blowing flow control method. The method can be achieved by cyclically arranging suction and blowing on the undersurface of the bridge. The effectiveness of the method for the vertical and torsional VIV of the bridge sectional model is verified through wind tunnel tests. The test results imply that the best perturbation position of the ESBM is the leading edge of the undersurface of the bridge. For dimensionless spanwise distances of 2–4 with single-hole flow coefficients of 2.27 × 10−3–3.03 × 10−3 and 1.45 × 10−3–1.94 × 10−3 during vertical and torsional VIV, respectively, the VIV can be completely suppressed. The results of the wake analysis show that this method can effectively suppress the scale of the spanwise vortex of the bridge, causing the VIV to disappear.