This study reports the preparation of 3D hierarchical carbon nanotube (CNT) @MnO2 core-shell nanostructures under assistance of polypyrrole (PPy). The as-prepared CNT@PPy@MnO2 core-shell structures show a perfect coating of MnO2 on each CNT and, more importantly, a robust bush-like pseudocapacitive shell to effectively increase the specific surface area and enhance the ion accessibility. As expected, a high specific capacity of 490-530 F g-1 has been achieved from CNT@PPy@MnO2 single electrode. And about 98.5% of the capacity is retained after 1000 charge/discharge cycles at current density of 5 A g-1. Furthermore, the assembled asymmetric CNT@PPy@MnO2//AC capacitors show the maximum energy density of 38.42 W h kg-1 (2.24 mW h cm-3) at power density of 100 W kg-1 (5.83 mW cm-3), and maintain 59.52% of the initial value at 10,000 W kg-1 (0.583 W cm-3). In addition, the assembled devices show high cycle stabilities (89.7% after 2000 cycles for asymmetric, and 87.2% for symmetric), and high bending stability (64.74% after 200 bending tests). This ability to obtain high energy density at high power rates while maintaining high cycle stability demonstrates that this well-designed structure could be a promising electrode material for high-performance supercapacitors.