The authors took Jianghai Zhida Bridge plan Ⅰ, Jianghai Zhida Bridge plan Ⅱ and 3rd Nanjing Yangtze River Bridge as examples. Based on the stress state of the main beam, the allowable amplitudes of bending vortex-induced resonance of steel bridge towers were calculated and the relationship between the allowable amplitudes and tower height was studied. An estimation formula for the allowable amplitudes of bending vortex-induced resonance of steel bridge towers were determined with the parameter of tower height. For self-supporting bridge tower, the allowable amplitude of bending vortex-induced resonance of the tower was estimated. When the allowable amplitude of vertical vortex-induced resonance of the beam reached its maximum value, a ratio between the vertical bending stress at the key section and the permissible bending stress of the steel for the beam was used for the estimation. The wind tunnel tests for aeroelastic models of bridge towers were conducted. The results show that the ratio between the maximum allowable bending stress produced by main beam vertical vortex-induced resonance and the allowable bending stress of the steel for the beam is a certain value. When the amplitude of the towers produced by the tower vortex-induced resonance reaches the maximum allowable values, the ratio between the vertical bending stress at the key section and the allowable stress of the steel for the beam is also a certain value. The maximum allowable amplitude ratio of bending vortex-induced resonance of steel bridge towers is about 0.12%. The results can provide reference for the determination of allowable amplitude for vertex-induced resonance of large-span bridge towers.