Vanadium pentoxide thin films were prepared by thermal evaporation of V2O5 powder followed by annealing posttreatment in air. Lithium was inserted electrochemically from an electrolyte so that Lix V2O5 (0≤x≤0.54) was obtained. The normal transmittance and reflectance spectra were measured and optical absorption coefficient was calculated. X-ray diffraction analysis has showed that the posttreated V2O5 thin films were microcrystal structure. The optical absorption spectra of all films have exhibited two distinct regions of behavior: a high-energy region in which (αhν)1/2 varied linearly with hν and a low-energy tail. The dividing energy of the two distinct regions depends on electron and Li ion intercalation. The present results have given that the anode electrochromism of V2O5 thin films is shift of absorption edge, and the cathode one is absorption of small polarons in V2O5.