Taking epoxy resin as an example, this research demonstrates that characteristic parameters of charge transport and accumulation are obtainable from complex permittivity spectra by carrying out theoretical analysis based on the electrode polarization theory. The real and imaginary permittivity of the electrode polarization satisfy the Cole-Cole relations well at and above 160°C. The shape parameter of the Cole-Cole arc is found to be an indication of ion blockage at the electrodes. Both the density and mobility of ions are thermally activated and the sum of the activation energies of these two thermal processes is nearly equal to the activation energy of ac conductivity in the same temperature range. This very reasonable result indicates the adequacy of electrode polarization analysis.