A low-cost and environmentally friendly hydrothermal method was utilized to prepare reduced graphene oxide (rGO) and synthesize rGO/alpha-Fe₂O₃composites with different rGO contents. The chemical composition and morphological essence of the as-prepared samples were characterized through multiple techniques. The results indicated that the uniform alpha-Fe2O3 cubes adhered uniformly on both sides of the crumpled and rippled rGO sheets. In addition, a series of resistive-type gas sensors were fabricated based on the as-prepared rGO/α-Fe₂O₃composites as well as pureα-Fe₂O₃to compare their gas-sensing properties toward acetone vapor. The composite containing 1.0 wt% rGO exhibited an enhanced gas response and its response time was shortened to 2 s. We attribute it to the extension of electron depletion layers, the change of charge carrier concentration, which are caused by the formation of local p-n heterojunctions when introducing rGO.