A polyaniline/tin oxide hybrid, which has a conductivity of 3–6Scm−1 at 25°C, has been prepared by the oxidative polymerization of aniline with the simultaneous hydrolysis of SnCl4 and an appropriate post-processing temperature. As an electrode material, 5–20nm pore-dominated polyaniline/tin oxide hybrid gave an improved electrochemical capacitance performance due to providing an effective electrochemical accessibility of electrolyte solution. The charge/discharge tests showed that the polyaniline/tin oxide hybrid had a higher specific capacitance than that of polyaniline with a growth of current density from 1.0Ag−1 to 30Ag−1, and the specific capacitance of polyaniline/tin oxide hybrid still reached 325Fg−1 at a constant current density of 30Ag−1, but that of polyaniline was about 180Fg−1.