Abstract: With the development of human society, the combustion of fossil fuels and various anthropogenic activities have led to a sustained increase in atmospheric CO₂ concentration. Concurrently, significant wastewater discharge has contributed to elevated nitrate ion (\textNO_3^- ) levels in aquatic environments. The conversion of CO₂ and \textNO_3^- into high-value urea using renewable solar energy represents a pivotal strategy for mitigating pollution and carbon emissions, while promoting resource recycling of these compounds. In this study, we synthesized a ZnO-O_v/Cu₂O composite catalyst through electrochemical deposition and photodeposition methods. The catalyst was employed for the photoelectrocatalytic co-reduction of CO₂ and \textNO_3^- to synthesize urea. The experimental results demonstrate that ZnO-O_v/Cu₂O achieved a Faradaic efficiency (FE) of 11.4% and a urea yield of 41.4 μmol·g_cat.⁻¹·h⁻¹ at potential of −0.8 V vs. RHE, which are 1.79 times and 3.3 times than that of pure ZnO (FE: 6.3%; yield: 12.5 μmol·g_cat.⁻¹·h⁻¹), respectively. Combined with the results of electrochemical impedance spectroscopy (EIS) and UV-visible diffuse reflectance spectroscopy (DRS), the introduction of oxygen vacancies and Cu₂O significantly improve the photoadsorption, separation and migration efficiency of photogenerated charge carrier and provide additional abundant Cu⁺ catalytic active sites, thus enhancing the performance of photoelectrocatalytic urea synthesis. This work provides theoretical guidance for the development of advanced catalysts for photoelectrochemical urea synthesis and other sustainable applications, offering an environmentally friendly strategy for pollution control and carbon reduction.