Herein we present the synthesis of Ag/SnO2/reduced graphene oxide (rGO) ternary nanocomposites (NCs) through one-step route. Many methods were employed to investigate the phase and morphological structure of the prepared composites. The coexisting of SnO2 and Ag can be confirmed by X-ray diffractometry and X-ray photoelectron spectroscopy analysis and a large number of nanoparticles decorated on the surface of rGO are observed from field-emission scanning electron and transmission electron microscopy images. The composites were employed to fabricate gas sensor to detect TEA gas. The Ag/SnO2/rGO sensor exhibits higher response to TEA gas at a low working temperature of 220 degrees C compared with SnO2 and SnO2/rGO. This markedly enhancement of TEA gas-sensing performance may be related to the well catalytic activity and higher specific surface area of the Ag/SnO2/rGO NCs.