In this paper, 80 magnetic storms during 1973-1977 are analyzed by means of the Fast Fourier Transform (FFT). The data were selected from the three observatories of Beijing, Qing Guang and Chang Li.It is get the general nature of the magnetic storm spectral components by the dispersion formula of FFTin some local areas. It is find the spectral features are nearly the same at the three observatories. The storm spectral amplitude decreases with increasing frequenecy and are linear in the logarithmic coordinate. This linear trend is obvious especially for the period range from 0.5 hours to 6.8 hours.It is calculated the spectral slopes b in this period range by means of the weighted least square fitting method, and the storm energy utilizing the parsval energy equation. All the spectral slopes of magnetic storm are close to each other. So the energy partitioning law for frequency of storm spectra is consistent.The above result is of value to a further study of the physical mechanism of magnetic storms, the physical nature of storm source, and the solar-terrestical relationship.