For super-tall and long-span structures, wind-induced vibration possesses a threat to the structural safety. It is important to model and analysis the wind load. The fluctuating wind power spectra in given specifications could only reflect the second-order probabilistic characteristic, which indicates that it is not capable of fully expressing the stochastic wind field. Besides, the popular Fourier transfer algorithm cannot achieve a high estimation accuracy and high resolution. In view of this problem, a high-resolution nonparametric spectral estimation algorithm-amplitude and phase estimation (APES) is used to estimate the fluctuating wind amplitude and phase spectrum, using the field measured wind velocity data of a certain cable stayed bridge. Through statistical analysis，the mean value of the amplitude spectrum and phase spectrum, as well as the distribution type at different frequency points, are obtained, thus to improve the modeling accuracy of the fluctuating wind spectrum, which is important in anti-wind design and safety assessment.