Abstract: In this paper, the Fourier Spectrum and Bessel Spectrum of ionospheric scintillation intensity are calculated by Riometer data of 17 events of CNAhappended during Sept. and Dec. in 1986. The value of power index of Fourier Spectrum, shift velocity of irregularity in ionosphere and scintillation index are found out. The Spatial Spectrum of phase fluctuation follows the power law are found out too. Depend on that the Fourier spectrum follows a power law, the power index is a negative number and the relation between the power index and the fractional demension, the fractional demetmon is about 2.45. It is shown that this fraction de-mension is also the fraction demension of the irregularity. It is the reason to be supposed in this paper that ionospheric irregularities are a separetory fractal and are not a separetory patch. And a Fractal model of ionospheric irregularity of F-layer in polar is also suggested.