Electric double layers (EDL) with different dielectric constants in the condensed layer, outer diffuse layer and bulk solution were theoretically studied by considering the steric effect of ions with the EDL. The expressions of condensed layer thickness, total charge and capacitance of the EDL are derived, and their variation with the bulk ion concentration, applied voltage and the dielectric constant in DL are evaluated and analyzed. The calculation results show that the thickness of condensed layer in EDL grows with the ion concentration in bulk solution and the applied voltage, the total charge is highly related to the applied voltage, and the capacitance significantly change with the variation of bulk ion concentration and condensed layer permittivity. The theoretical evaluation could serve as a reference for guiding the design of applications related to micro/nano fluidic and electronic devices, or the analysis of the EDL existing in material interfaces.