Poplar wood pulp was adopted as both frame and precursor for the synthesis of pulp fiber (PF)/reduced graphene oxide composite via a simple and low-cost method. In this method, the PF based on graphene (PFG) composite film electrode was prepared by a simple vacuum filtration process with various ratios (PF: reduced graphene oxide (RGO) = 5:1, PF:RGO = 5:2, PF:RGO = 5:3, PF:RGO = 5:4, PF:RGO = 5:5). In terms of special structures, the PFG can be used as electrodes without metal-collector, adhesives, and additives. The optimal ratio (PF:RGO = 5:4) film electrode displayed a high areal-specific capacitance of 683 mF/cm2 at 1 mA/cm2 with a mass of 5.3 mg/cm2 (specific capacitance of 129 F/g) and good cycling stability (87.5% capacitance retention after 10,000 cycles at 5 mA/cm2) as well as excellent rate capability and high flexibility (suitable for any angle, even 180°). Moreover, the device could possess a maximum energy density of 47.71 μWh/cm2 and a maximum power density of 1251 μW/cm2. These results suggest that the composite PGF film is a promising electrode material.