Abstract: Spectrum parameter of wind profile radar (WPR) is one of the important parameters to generate basic data products. Correctly estimation is the basis of WPR application. Based on the assumption that the clear air follows the gauss distribution, two criteria to obey Gaussian distribution are given to judge the return signal power spectrum of clear air. One is mean-square deviation, and the other is the relative area ratio. Using the two criteria, the paper statistically analyzed the case of WPR’s clear sky sounding data obeyed Gaussian distribution. Then analyzing the possible atmosphere return-signal with clutters and elimination method, and reaching the conclusion of clear air return signal power spectrum subject to Gaussian distribution, which provided a new method to fast estimate spectral parameters. That was power spectrum peak position corresponding to doppler frequency shift, and the relative location of the peak half-power point corresponding to spectrum width.