In this work, a novel branched heterostructural composite composed of nanorods ZnO backbone and SnO₂branches was prepared via a facile one-step hydrothermal method. The morphology, structure and component of the SnO₂/ZnO composite was characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and elemental mapping analysis. The evolution process of the SnO₂/ZnO composite was observed by SEM that the SnO₂branches gradually grow on ZnO backbones. The composite with novel heterostructure was applied as the sensing material for the fabrication of gas sensor, and their gas sensing properties were tested for response to various gases. Compared to pure ZnO gas sensors the branched SnO₂/ZnO gas sensor exhibited enhanced gas sensing properties toward ethanol, giving a response of 18.1-100 ppm.