Based on highfrequency force balance technique in a boundary layer wind tunnel, the root mean square (RMS) coefficients of generalized force and the analytical model of the generalized force spectra of the first mode of typical lattice towers in alongwind direction were proposed. And the generalized force spectra were deduced from deriving the method of the first mode and generalized force spectra of higher modes by mode shape corrections of generalized force spectra. The top RMS acceleration responses in aeroelastic model of three typical lattice towers were evaluated by using the generalized force spectra. And compared with experimental data of wind tunnel, the influence of mode shape corrections and the contributions of higher modes and aerodynamic damping on windinduced dynamic responses were analyzed and several conclusions were drawn.