Abstract: TiO₂ nanowires were prepared on F-dopet tin oxide(FTO) by hydrothermal method. Then WO₃ nanowires were prepared on TiO₂ nanowires by hydrothermal method to obtain WO₃/TiO₂ composite films. The electrochromic properties of WO₃/TiO₂ composite films were studied by cyclic voltammetry (CV), chronoamperometry (CA) and chronocharging (CC). The response time of the coloring and bleaching state of the film was tested by UV spectrophotometer.Through the above tests, the parameters such as cycle stability, light modulation, coloring efficiency and switching time (Y and X) were calculated. The results show that the electrochromic properties of WO₃/TiO₂ composite films are obviously improved. The reversibility of WO₃/TiO₂ composite films increases by 6%, and the coloring efficiency increases by 40.96 cm²/C.