In this study, one-dimensional (I D) tungsten oxide nanobundles (TNB) were synthesized via a simple solvothermal method. The phase of I D tungsten oxide was W 18049, and the diameter and length of the building units (nanowires) were about 7 and 800 nm, respectively. TNB films were fabricated by the Langmuir-Blodgett (LB) method. The locally arranged domains of the long nanobundles form the LB films, but it is difficult for them to align perfectly owing to the inter-nanobundle interaction and dispersion problems. The electrochromic (EC) property of the TNB LB films was characterized by electrochemical potential cycling tests and in situ transmittance measurement. The deposition condition of the LB films influenced their EC property. The heat treatment and surface pressure of the TNB LB films plays an important role in the response time and transmittance of the TNBs. (c) 2007 Elsevier B.V. All rights reserved.