In this paper, we present fabrication of a nano-composite Prussian Blue (NPB) film to synchronously improve the contrast and switching time of regular Prussian Blue (PB) film by applying the concept of nano-technology. The NPB consists of indium tin oxide (ITO) nano-particles (3.0 +/- 1.0 Omega +/- 40 5 nm) as a medium layer for PB to gain larger operative reaction surface area in Li+ based electrolyte (1 M LiClO4/PC) system. The procedures for preparation of NPB are: first, a well-dispersed ITO nano-particle solution is sprayed onto ITO glass (30 Omega/sq) at 200 degrees C; the PB film is then electroplated onto the pre-sprayed ITO nano-particles. Since ITO nano-particles can be well covered with PB, the NPB film forms a nano-porous electrochromic layer. The switching speed and contrast of NPB exhibit much better performances than traditional PB thin films. The structure, morphology, and electrochromic properties were characterized by scanning electron microscopy (SEM), cyclic voltammograms (CV), and UV-vis spectroscopy. (c) 2006 Elsevier Ltd. All rights reserved.