The flexible polyindole/carbon nanotube/bacterial cellulose (PIn/CNT/BC) nanofiber nonwoven electrode is prepared by a two-step method combination of 'electrospinning and electrospray' process and potentiostatic polymerization. The structure and morphology of the as-prepared PIn/CNT/BC nonwoven electrode are investigated by Scanning electron microscopy, Transmission electron microscopy, Fourier transform infrared, Brunauer-Emmett-Teller and Energy dispersive spectroscopy. The PIn/CNT/BC electrode has a hierarchy configuration with a broccoli-like rough surface consisting of BC electrospun nanofibers, CNT coating layer and PIn nanoparticle layer, which play the function of supporting substrate, conductive path and electrode active material, respectively. To evaluate the electrochemical properties of PIn/CNT/BC electrode, cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy tests are performed. The unique structure ensures that the flexible PIn/CNT/BC nanofiber nonwoven electrode exhibits larger specific capacitance up to 552.6 F g(-1), longer operation life with 95.6% capacitance retention after 5000 cycles, better conductivity with a fitting value of charge-transfer resistance of 9.87 omega, outstanding flexibility and stability with specific capacitance retention over 96.4% after 1500 bending cycles. The remarkable electrochemical performance of PIn/CNT/BC nanofiber nonwoven electrode offer promising applications as flexible energy storage device for wearable and smart electronic components.