In this study, nano-polyanline and manganese oxide nanometer tubular composites (nano-PANI@MnO2) were prepared by a surface initiated polymerization method and used as electrochemical capacitor electrode materials; and the effect of aniline amount on the microstructure and electrochemical performance was investigated. The microstructures and surface morphologies of nano-PANI@MnO2 were characterized by X-ray diffraction, scanning electron microscopy and fourier transformation infrared spectroscope. The electrochemical performance of these composite materials was performed with cyclic voltammetry, charge–discharge test and electrochemical impedance spectroscopy, respectively. The results demonstrate that the feed ratio of aniline to MnO2 played a very important role in constructing the hierarchically nano-structure, which would, hence, determine the electrochemical performance of the materials. Using the template-assisted strategy and controlling the feed ratio of aniline to MnO2, the nanometer tubular structure of nano-PANI@MnO2 was obtained. A maximum specific capacitance of 386 F/g was achieved in aqueous 1 mol/L NaNO3 electrolyte with the potential range from 0 to 0.6 V (vs. SCE).