The Pt nanocrystals as nanonetwork conductors improved electrochromic properties of TiO2 such as increased optical modulation and fast response time, compared to pure TiO2 as well as TiO2 incorporated by amorphous Pt nanophases. It is likely that an enhancement of cathodic electrochromism in TiO2-Pt is due to an improved injection or extraction of electron/proton caused by Pt nanocrystals.