Conductive polymer (CP) fabric is considered as the ideal electrode for flexible energy storage due to its light weight, good flexibility and high energy storage properties. However, the conventional polymer-coated cellulose fiber synthesized by liquid-phase oxidation polymerization always forms disordered assembly of polymer particles on fiber, which endures poor mechanical stability. Here, we report a two-dimensional (2D) CP based fabric electrode realized by a salt-template assisted vapor-phase polymerization method, which achieves robust coating of 2D CP on various cellulose fibers. Typically, the prepared 2D polypyrrole@cotton electrode displays a high specific capacitance (902.6 mF cm−2) and good cycling stability (86.5% capacitance retention after 12,000 cycles). The capacitance of flexible symmetrical device retains at more than 90% when it is bent to 180° after 1000 bending cycles. This work provides a new strategy for the robust interface between functional materials and cellulose fibers, and has great potential for commercial mass production.