The relationship of the conductivity with frequency for an amorphous fast lithium ion conducting material B2O3-0.7Li2O-0.7LiCl was studied. The results showed that: in a quite wide frequency range the bulk conductance was equal to the total conductance for the specimens; the frequency spectra of the conductivity showed a plateau and a rise in the intermediate and higher frequency range, respectively; and the frequency at which the conductivity began to increase became higher with rising of temperature. As a result of the features of such amorphous material, the measurement of the conductivity may be carried out by use of the a.c. bridge or the a.c. V-A method and thus be simplified. Considering the effect of the long range disorder in the non-crystalline solid on the ionic transport, we praposed a mechanism of the local polarization and explained the features of the spectra of conductivity and its dependence on temperature.