Integrating semiconductor photocatalysts with outstanding visible light absorption and fast surface/interface charge transfer kinetics is still an enormous challenge for efficient CO₂ photoreduction. In this work, the Au nanoparticles have been coupled with ultrathin BiOBr nanosheets, the formed heterostructure (Au/BiOBr) possesses a localized surface plasmon resonance (LSPR) and enhances the visible light absorption ability, as well as forms a fast charge transport channel on the interface between Au and BiOBr. Thus, the heterostructure photocatalyst exhibits higher photocatalytic CO₂ to CO performance (135.3/16.43 μmol g⁻¹) than that of BiOBr (89.0/6.46 μmol g⁻¹) under 300 W Xe lamp and visible light (λ > 400 nm) irradiation for 5 h, respectively. Finally, the in situ FT-IR spectroscopy revealed CO₂ photoreduction process and found that the *COOH is the key intermediate for CO₂ to CO. This work provides an effective method to construct multielectron transfer scheme for efficient photocatalytic CO₂ reduction.