A novel hydrothermal process using p-nitrobenzoic acid as structure-directing agent has been employed to synthesize plate-shaped WO3 nanostructures containing holes. The p-nitrobenzoic acid plays a critical role in the synthesis of such novel WO3 nanoplates. The morphology, structure and optical property of the WO3 nanoplates have been characterized by transmission electron microcopy (TEM), scanning electron microcopy (SEM), X-ray diffraction (XRD) and photoluminescence (PL). The lateral size of the nanoplates is 500-1000 nm, and the thickness is about 80 nm. The formation mechanism of WO3 nanoplates is discussed briefly. The gas sensitivity of WO3 nanoplates was studied to ethanol and acetone at different operation temperatures and concentrations. Furthermore, the WO3 nanoplate-based gas sensor exhibits high sensitivity for ethanol and acetone as well as quick response and recovery time at low temperature. (C) 2010 Elsevier Ltd. All rights reserved.