Abstract: To investigate the problem of classical two-scale sea surface model, which can not effectively analyze the non-Bragg scattering at high sea state and low grazing angle, a more practical scattering model for one-dimension (1-D) time-varying sea surface is adopted, in which a chirp parameter is employed to describe the changes of Doppler frequency. Then, the angular scattering characteristic of the improved model is investigated based on the mean scattered power. Next, the Fractional Power Spectrum (FPS) of the improved model is analyzed, which shows that the FPS of the scattered field is found to be distributed as sum of impulse signals and the peaks are relative to the frequency parameters of the improved model. Finally, X-band real sea data is used for verification and the influences of incident wavelength and transform angle on the FPS are discussed. The results prove that the improved model is suitable for the analysis and extraction of the frequency changes and Doppler shift for the time-varying sea surface.