Au/CeO₂(111), as an important catalyst system, has demonstrated excellent catalytic performance in a variety of fields such as the catalytic oxidation and the water-gas shift reactions. In order to deeply reVeal Au/CeO₂(111) catalytic mechanism, especially to understand the interaction of the active components on the atomic scale. In this paper, the adsorption properties on the Au/CeO₂(111) surface are investigated by calculating the adsorption energy, differential charge density, Bader charge, and the density of states using density functional theory (DFT+U). First, five adsorption sites of Au/CeO₂(111) were identified in the planar region of CeO₂(111), and the most stable adsorption configuration was found to be located at the bridging position between surface oxygen atoms (the oxygen-oxygen bridging site). It suggests that Au interacts more closely with the oxygen-oxygen bridging sites. Further, the differential charge density and Bader charge reVeal the charge transfer mechanism during the adsorption process: the Au atoms are oxidized to Au⁺, while the Ce⁴⁺ ions in the second nearest neighbor of Au are reduced to Ce³⁺, and the adsorption process is accompanied by a charge transfer phenomenon. Au also exhibits a unique adsorption behavior in the CeO₂(111) step-edge region, where a highly under-allocated environment is formed due to the decrease in the coordination number of atoms in the step edge, which enhances the adsorption of Au in a highly under-allocated environment. The adsorption of Au at the step edge is enhanced by the lower coordinated environment due to the reduced coordination number of the atoms at the step edge. By comparing four different types of step structures (Type I, Type II, Type II*, and Type III), we find that the higher adsorption energies of Au at the Type II* and Type III sites are mainly attributed to the lower coordinated state of Ce atoms at these sites. Charge transfer is also particularly pronounced at the Type III sites. It is also accompanied by electron transfer from Au to Ce⁴⁺ ions, making Type III the preferred adsorption site for Au atoms. By constructing a more comprehensive Au/CeO₂ model, this study breaks through the preVious limitation of focusing only on planar adsorption and reVeals the adsorption mechanism of Au/CeO₂ at the edge of the step, which provides a new perspective for us to deeply understand the catalytic mechanism of Au/CeO₂(111).