Abstract: For the wind tubrines in their running conditions, their seismic responses involve the combined excitation of wind and earthquake loadings. In order to establish an uncoupled analysis method for the dynamic response of wind turbines excited by wind and earthquake, a bilinear simplified model for the aerodynamic damping ratios of horizontal-axis wind turbines was established by the least square method first. An uncoupled seismic response analysis method was built up where the aerodynamic damping forces on the rotor were replaced by equivalent modal aerodynamic damping ratios added to the support structure. The simulation results of this uncoupled method were compared with those of the coupled one to evaluate the reliability of this decoupled model. The analysis result indicates that the bilinear model can describe the regularity of modal aerodynamic damping ratios with respect to mean wind speed at the hub-height. Both errors of tower-top acceleration amplitudes and tower-base bending moment amplitudes obtained by the uncoupled and coupled method are less than 15 %. In addition, the computational efficiency of this uncoupled method is higher than that of the coupled one.