Nanostructured composite web were prepared with multi-walled carbon nanotube (MWCNT) in polyacrylonitrile (PAN) by electrospinning technology. The diameters of the fibers showed narrow distribution to be averaged of 300㎚. The alignment of MWCNT along the fiber direction has been successfully achieved. The MWCNT/PAN composite fiber web was oxidatively stabilized in air and followed by steam activation, resulting in activated carbon nanocomposite fibers (ACNCFs). 1wt.% addition of MWCNT increased the specific capacitance by two times more from 82 to 160F/g. The enhancement of the capacitance was well explained by the increase in the specific surface area and the reduced resistance by the addition of MWCNT.