Abstract:WO3/Au composite film electrode was prepared by hydrothermal combined electrodeposition method. The samples were characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD), and the results showed that WO3/Au composite film was synthesized. Electrochemical and spectral measurements were carried out to obtain the electrochromic response time, reversibility, coloration efficiency (CE) and transmittance of the WO3/Au composite film. The photoelectrochemical properties of the samples were characterized by measuring photocurrent and photocatalytic degradation efficiency. The results show that compared with pure WO3 nanoblocks, WO3/Au composite film improves the electrochromic property, photocurrent and photoelectric catalysis activity. Among them, WO3/Au composite film prepared by depositing Au nanoparticles in 80 s showed the highest electrochromic property, photocurrent and photoelectric catalysis activity. Meanwhile, compared with direct photocatalysis (DP) and electrocatalysis (EC), the photoelectrocatalysis (PEC) activity of the composite film is the highest.