In this work, polyamidoamine (PAMAM) dendrimers are used as templates to synthesize nanotree-like polyaniline (PANI) materials, which are further used as electrode materials for supercapacitors. Effects of PAMAM content on PANIs’ structural characteristics and electrochemical properties are investigated detailedly. SEM images show that at 0.1 % PAMAM content, the PANI presents a stable self-assembled dendritic structure composed of many nanorods. Compared with pure PANI, nanotree-like PANI has better crystallinity, higher doping degree, larger high surface area and better reactivity. At a current density of 1 A g−1, the PANI nanotree electrode displays a high specific capacitance value of 812 F g−1, which is 119 % higher than that of pure PANI. Even after 1000 cycles, it still maintains about 69 % of the initial capacitance, showing good electrochemical stability. Thus the PANIs with nanotree structures are promising electrode materials for high-performance electrical energy storage devices. Moreover, the possible electrochemical enhancement mechanism of PANI nanotree electrode for supercapacitor is also discussed.