Abstract: In recent years, magnetic fields have been widely applied in catalysis to increase the performance of electrocatalysis, photocatalysis, and thermocatalysis through an important noncontact way. This work demonstrated that doping CsPbCl₃ halide perovskite nanocrystals with nickel ions (Ni²⁺) and applying an external magnetic field can significantly enhance the performance of the photocatalytic carbon dioxide reduction reaction (CO₂RR). Compared with its counterpart, Ni-doped CsPbCl₃ exhibits a sixfold increase in CO₂RR efficiency under a 500 mT magnetic field. Insights into the mechanism of this enhancement effect were obtained through photogenerated current density measurements and X-ray magnetic circular dichroism. The results illustrate that the significant enhancement in catalytic performance by the magnetic field is attributed to the synergistic effects of magnetic element doping and the external magnetic field, leading to reduced electron‒hole recombination and extended carrier lifetimes. This study provides an effective strategy for enhancing the efficiency of the photocatalytic CO₂RR by manipulating spin-polarized electrons in photocatalytic semiconductors via a noncontact external magnetic field.