Uniform three-dimensional (3D) mesoporous nest-like Bi2WO6 nanoarchitectures with scales of 3~4nm were synthesized via a facile template-free hydrothermal process.XRD, XPS, FE-SEM, HR-TEM,UV-Vis-DRS and BET techniques were employed to investigate the phase composition, morphology, and microstructure, spectra property.Nitrogen adsorption and desorption isotherms were conducted to examine the specific surface area and the pore nature of the as-prepared sample.Gas sensing tests showed that the Bi2WO6 nanoarchitectures have potential applicantions in fabracating ethanol gas sensors, and a plausible enhancement gas responding mechanism of nest-like Bi2WO6 sensors was proposed based on the structure and response/recovery properties.