A new method is proposed in this paper to improve the precision of spectrum correction of damped free vibration response based on frequency-domain. The principle of this method is that a length of continuous, free, damped vibration signal is sampled and its analytical signal is constructed, then N points Fast Fourier Transform (FFT) is performed to the analytical signal from its starting data point and the (L+1)-th data point. Finally, the modal parameters are calculated by the parameters of two corresponding peaks of amplitude spectrums. This method can reduce the spectral leakage of negative frequency component caused by FFT. Results of Simulations show that the precision of spectrum correction can be rather high when the natural frequency of each modal parameter is far from the others. However, the method cannot be used if one natural frequency is very close to the others or the modal coupling is very serious.