This study focuses on the electrochromic device (ECD) applications of poly(3,4-ethylenedioxythiophene)/tungsten oxide (PEDOT/WO3) hybrid nanofibers prepared via electrospinning method. Nanoporous WO3 films were initially electrosynthesized on Pt sheet. The PEDOT layer was electropolymerized onto the entire surface of the WO3 nanoporous host framework in the presence of different ionic liquids: 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), 1-butyl- 3-methylimidazolium bis(trifluoromethylsulfonyl) imide (BMIMTFSI), and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide (BMPTFSI). The morphological features and elemental surface characterization of hybride nanofibers were monitored by scanning electron microscopy and energy dispersive X-ray spectroscopy. ECDs changed color reversibly from transparent to light brown by switching from +3V to -3V. It was found that the highest optical modulation of 47.89% and maximum coloration efficiency of 363.72cm(2)/C is achieved for PEDOT/WO3/BMIMPF6 based electrochromic device. Hybrid nanofibers exhibited excellent long term stability even after 1000 chronoamperometric cycles. This work could not only push forward the facile preparation of PEDOT/WO3 nanofibers but also represent, for the first time, the possibility that the hybrid nanofibers could be a promising material for the highly efficient ECDs.