This paper studied the aeroelatic effect on tall buildings. An aeroelastic model was designed and manufactured for wind tunnel tests. With the time-history responses of the structure obtained from the aeroelastic model in the wind tunnel test, we could identify the structural dynamic characteristics by spectral analysis, and get the aerodynamic damping from the natural excitation technique method (NExT), the ARMA method, combined with a change in mode order, and then study the rules of aerodynamic damping changing with wind speeds. In a strong wind situation, filter technique was used to analyze the along-wind time-history acceleration response to eliminate the influence of the across-wind energy transfer. And vortex-excited resonance existed in the process of identifying the aerodynamic damping. The peak acceleration responses of the rigid models by pressure test and high-frequency-force-balance test, which considered the aerodynamic damping ratios, were very close to the results of the aeroelastic model test. The accuracy of the aeroelastic model test was verified. For the rigid models, irrespective of aerodynamic damping ratios, the peak acceleration responses were much larger than the results of the aeroelastic model test. The biggest difference was 41%. However, in some cases, the aerodynamic damping ratios increased the responses, and the necessity of considering the aerodynamic coupling effect on the wind-resistant design of flexible high-rise buildings has been verified.