Potentialities of the method of bilayer thin-film electrolyte electrophoretic deposition onto cathodic substrate are analyzed. Ce0.8Sm0.2O1.9–δ (SDC) nanopowder and BaCe0.89Gd0.1Cu0.01O3–δ BCGCuO) micropowder are prepared by the methods of laser evaporation–condensation and pyrolysis, respectively. The effect of ultrasonic treatment on the SDC and BCGCuO particle distribution in suspensions and their electrokinetic properties are studied. The using of the ultrasonic treatment combined with centrifugation allowed obtaining an aggregative-stable suspension of the BaCe0.89Gd0.1Cu0.01O3–δ micron particles in the isopropanol–acetylacetone mixed medium (70/30 v/v) that is characterized by high zeta potential. Ce0.8Sm0.2O1.9–δ and BaCe0.89Gd0.1Cu0.01O3–δ thin films are obtained at the La2NiO4 +δ cathode substrate using electrophoretic deposition; microstructure and electric properties of the prepared thin-film structures are studied. The conductivity and electric properties of the bilayer electrolyte were found to be determined by the Ce0.8Sm0.2O1.9–δ film properties. Despite the sintering high temperature, the grain structure of the BaCe0.89Gd0.1Cu0.01O3–δ film is underdeveloped; this is determined by the micron powder properties.