Construction of a micro-/nanostructured TiO2 film has been considered to be an important way to enhance the electrochemical properties and electrochromic performance of the material. Herein, we investigated the electrochromic properties of a nanocomposite TiO2 film prepared by decorating rutile a TiO2 nanowire (TiO2 NW) array with anatase TiO2 nanoparticles (TiO2 NPs) via a facile two-step synthesis method. Owing to its large active surface area and high transparency, the TiO2 NW–NP composite film supported a greater number of sites for Li+ ion intercalation and extraction. As a result, the TiO2 NW–NP film displayed higher optical contrast, coloration efficiency and transient current density compared with NW and NP films, demonstrating that enhanced electrochromic properties could be achieved using the NW–NP composite structure.