Ordered mesoporous Fe-In₂O₃has been synthesized via a nanocasting route using the three-dimensional (3D) cubic mesoporous KIT-6 silica as a hard template. Various techniques including X-ray diffraction (XRD)，nitrogen adsorption-desorption and transmission electron microscopy (TEM) as well as X-ray photoelectron spectroscopy (XPS) were employed for the material characterization. All the results demonstrate that the obtained Fe-doped In₂O₃displays the high surface area，ordered mesoporous structure and well crystallite. The NO₂sensing properties of the sensors based on mesoporous pure In₂O₃and Fe-doped In₂O₃samples were detected by a static test system. The sensor utilizing mesoporous Fe-doped In₂O₃exhibits much higher response to NO₂gas compared to that using mesoporous pure In₂O₃prepared by the same nanocasting technique. The excellent gas sensing property of mesoporous Fe-doped In₂O₃is associated with its higher surface area and pore volume which induce highly effective surface interaction between the target gas molecules and the surface active sites. Moreover，the improved sensing behavior to NO₂has been linked to the incorporation of iron species on the sensor，favoring the effective adsorption of NO₂molecules on the surface. All the factors are obviously beneficial for enhancing the gas-sensing performance.