Here, we report the synthesis of Cu-doped CeO2 nanorods (denoted as Cu-CeO2-x, x represents the mass content (wt%) of the doped Cu) by a facile hydrothermal method, followed by thermal treatment in an H2/Ar atmosphere. As the electrocatalyst, Cu-CeO2-3.9 with a large surface area of 95.2 m2 g−1 and mesoporous structure exhibits high electrocatalytic activity toward the N2 reduction reaction (NRR), delivering an NH3 yield rate of 5.3 × 10−10 mol s−1 cm−2 and a faradaic efficiency of 19.1% at −0.45 V (vs. RHE) in a 0.1 M Na2SO4 electrolyte (pH = 6.3), much higher than the NRR performance achieved with pure CeO2 nanorods. The Cu doping can effectively tune the concentration of multiple oxygen vacancies in CeO2, thus resulting in significantly improved NRR activity.