Nanogold particles supported on metal oxide surfaces present unusually high catalytic performances in low-temperature oxidation reactions. Despite numerous studies on that matter, the molecular mechanism concerning O2 activation remains controversial. Aimed to identify the active sites for direct O2 activation on gold, a AuOOAu structure was analyzed by Hückel theory. It was found that an increase of Au–O orbital interaction can significantly promote O2 adsorption and dissociation. Therefore, we constructed a realistic model with a unique double linear OsAuOa structure at the perimeter of the Au/metal oxide interfaces, which was examined subsequently by DFT calculations. The double linear OsAuOa structure exhibited high reactivity, with O2 dissociation barriers as low as 0.12 eV and 0.17 eV for Au/TiO2 and Au/CeO2 systems, respectively. The present work gives new insight into the reaction mechanism of low-temperature oxidation reactions on gold catalysts.