Abstract: SrTiO₃ coating was applied to the etched aluminum foil by dip-coating with citrate solution.The influences of solution concentration,the amount of citric acid,immersing time,annealing temperature and time on the specific capacitance of the coated samples were studied.It was experimentally shown that the specific capacitance of the coated sample treated under 3×10^-3mol/L for 10min,and annealed under 550℃ for 1h would be the largest.In addition,the amount of citric acid had little effect on the specific capacitance.The capacitance was increased by about 15% after SrTiO₃ coating. The composite oxide films are promising to be used as the dielectric of electrolytic capacitor.