Photocatalytic CO₂ reduction is a promising method to resolve the energy shortage problem. Developing photocatalysts with strong redox capabilities is urgently needed to achieve high photocatalytic activity. Herein, we synthesized TiO₂/CsPbBr₃ S-scheme heterojunctions with modulated internal electric field by facet engineering of TiO₂ to control charge transfer for improved photocatalytic activity. Density functional theory (DFT) calculation reveals that there is a wider Fermi level difference between TiO₂-(1 0 1) and CsPbBr₃ than that between TiO₂-(0 0 1) and CsPbBr₃, which will induce more obvious band bending. Subsequently, more efficient spatial separation will occur around the interface. Thus, TiO₂-(1 0 1)/CsPbBr₃ heterostructures effectively reduce CO₂ into CO with the selectivity of 90.2 % and reduction rate of 12.5 μmol h⁻¹, 15.6 and 5.6 times improvement than that of 101-TiO₂ and TiO₂-(0 0 1)/CsPbBr₃, respectively. This report proposes a feasible idea of employing facet engineering to take the advantage of S-scheme heterojunction.