This paper shows a nanocomposite film of Dawson-type polyoxometalate (POM) K6P2W18O62 (P2W18) and TiO2 nanowires by combining hydrothermal and Layer-by-Layer (LbL) assembly methods The electrochemical and electrochromic (EC) performances were examined and compared with P2W18 and TiO2 composite film as well as individual P2W18 and TiO2 structures. The nanocomposite film exhibits improved EC properties with high transmittance modulation (45.1% at 650 nm), fast switching times (1.9 s and 6.7 s) and outstanding coloration efficiency (69.0 cm/C at 650 nm). The enhancement can be attributed to the contribution from P2W18 and TiO2, which displays large real active area and increase the capabilities for EC material. (C) 2017 Elsevier B.V. All rights reserved.