Abstract: It is the first report of study on the vacuum--evaporated electrochromic WO₃ film using EXAFS （Extended X-ray Absorption of Fine Structure）.During evaporation, the longrange of WO₃ powder-the precursor was vigorously destroyed and decomposed into many highly-dispersed dusters. The formed WO₃ film, compared to WO₃ powder, shortened in W-O distance and its lattice contracted. When it was cathodically colored in LiClO₄/propylene carbonate solution its lattice Cell further decreased. This condusion was also strongly supported by Raman spectra.