Abstract: In this paper, the HPbackscatter echo spectra measured by the technique of the pulse Doppler radar. The Doppler spectra are displayed in 3-dimensonal (time delay-power-Doppler frequency) spectrograms, i.e. the scatter function of the HPbackscatter propagation channal. The typical spectrograms are studied and the vertical motion velocity of the equivalent reflection height of the ionosphere are infered from the Doppler spectra. The values of the velocity are in accord with that infered from the vertical sounding data.