Double-shell SnO₂/alpha-Fe₂O₃hollow composites were synthesized by a low-cost and environmentally friendly hydrothermal strategy. Various techniques were employed for the characterization of the structure and morphology of hybrid nanostructures. The results revealed that the alpha-Fe₂O₃nanorods grew epitaxially on the surface of hollow SnO₂spheres, which were composed of primary nano-sized particles. The diameter of the alpha-Fe₂O₃nanorods was about 10 nm, and the thickness of the SnO₂spherical shell was about 100 nm. In order to explore the formation mechanism of the composites, the structure features of the double-shell structural SnO₂/alpha-Fe₂O₃hollow composites at different reaction stages were investigated. The ethanol sensing properties of the pure SnO₂and SnO₂/alpha-Fe₂O₃composites were tested. It was found that such double-shell composites exhibited enhanced ethanol sensing properties compared with the single-component SnO₂hollow spheres. For example, at an ethanol concentration of 100 ppm, the response of the SnO₂/alpha-Fe₂O₃composites was about 16, which was about 2 times higher than that of the primary SnO₂nanostructures. The response time of the sensor to 10 ppm ethanol was about 1 s at the operating temperature of 250℃.