In2O3/alpha-Fe2O3 (IFO) heterostructure nanotubes, with cubic-In2O3 nanocrystals randomly distributed on the surface of alpha-Fe2O3 nanotube-based backbones, were successfully prepared through a facile single-capillary electrospinning method. The morphologies of the resulting electrospun products were characterized by scanning electron microscopy and transmission electron microscopy. The crystal structures and components were determined by X-ray diffraction and energy-dispersive X-ray spectra, respectively. The results show that the morphology and structure of the products could be tailored by changing the content of indium nitrate in the precursor solutions and the calcination temperatures. Moreover, the IFO-0.1 (In/Fe = 1 : 9, molar ratio) nanotubes based sensor shows a high sensitivity to ethanol with a fast response/recovery time, and the performance is stable at a low operating temperature, which gives a potential application in ethanol gas sensors. A possible gas sensing mechanism based on the role of In2O3 in such a heterostructure is also discussed in detail.