The development of efficient photocatalysts with high activity and selectivity for coreduction of N2 and CO2 under ambient conditions represents a highly promising but still challenging strategy for sustainable urea synthesis. In this study, using density functional theory (DFT) calculations, we present a comprehensive descriptor strategy integrating geometric, electronic, and energetic factors to screen Cu-metal dual-atom photocatalysts (CuM/CeO2, where M = 27 transition metals) for urea synthesis. According to the screening of the catalyst stability, coadsorption capability of N2 and CO2, energy barriers of the rate-determining step (RDS), and urea desorption energies, CuMn/CeO2 emerged as the most promising candidate photocatalyst. Through comprehensive analysis of the effects of the Cu-Mn interatomic distance on catalytic performance, a robust volcano-type relationship was established between the energy barrier for the RDS and the formation free energy of the key intermediate NCON (ΔGNCON). This relationship was found to be independent of the support examined in this study.