Abstract: The hydrothermal parameters were optimized by orthogonal tests to prepare WO₃ nanowires with sodium tungstate as tungsten source, hydrochloric acid as regulator, ammonium sulfate as auxiliary agent, and then the reticular WO₃/poly 3,4-ethylenedioxythiophene (PEDOT) nanowire hybrid structure film was prepared by electrodeposition method. The structure and electrochromic properties of the film were studied. The results show that the electrochromic performance of WO₃ was optimal under hydrothermal reaction temperature of 190 ℃, time of 4 h and pH of 2, and the contrast was 80.6%. The WO₃/PEDOT film with hybrid structure of score-shell nanowire was successfully prepared by electrochemical deposition under optimal hydrothermal conditions, and the outer side of the WO₃ monocrystalline nucleus was covered by an amorphous thin shell. Compared with WO₃ nanowire and PEDOT, WO₃/PEDOT film showed excellent electrochromic and optical modulation properties, fast response speed and good cycling stability. The contrast of the film was 89.1% wth the coloring time of 3.4 s and the fading time of 2.2 s, and after 1 000 cycles, the contrast was retained 98.8%.