Mesoporous SnO₂ has been successfully prepared by the solvent-free infiltration method using SiO₂nanoparticles as template. The combined characterizations of X-ray diffraction pattern, nitrogen sorption isothermal, and transmission electron microscopy indicate the successful preparation of mesoporous SnO₂. It is found that the mesoporous SnO₂exhibits high response, good selectivity, fast response and recovery rate for detection of ethanol, which are much better than that of bulky SnO₂ prepared in the absence of SiO₂nanoparticles.