The vanadium pentoxide (V2O5)/carbon nanofiber composites (CNFCs) were prepared from polyacrylonitrile/V2O5 in N,N-dimethylformamide by a simple electrospinning method, and their electrochemical properties as supercapacitor electrodes were investigated. Different loadings of V2O5, the microstructures of the CNFCs (e.g., nanometer-size diameters, high specific surface areas, narrow pore size distributions, and tunable porosities) were changed, and the textural parameters significantly affected the electrochemical properties of the composites. The CNFC capacitors delivered the high specific capacitances of 150.0Fg−1 for the CNFCs in an aqueous, with promising energy densities of 18.8Whkg−1, over a power density range of 400–20,000Wkg−1. The CNFCs simultaneously exhibited excellent capacity retention.