Due to the synergistic effects of different metal sites, the double atom or multiple atomic catalysts are very promising for use in electrocatalysis. This paper focuses on the synthesis of urea [CO(NH₂)₂] under the synergistic effects of bimetallics. The heteronuclear diatomic molecular catalysts were designed and screened, and the details and energy information of the elementary reactions were provided from the atomic level using theoretical simulation, which provided a new understanding for the study of the reaction mechanism. It was found that the NbVN₆C catalyst was the best catalyst for the electrosynthesis of CO(NH₂)₂ (0.37 eV < 0.44 eV < 0.67 eV < 0.74 eV < 0.84 eV for NbVN₆C, TaVN₆C, WVN₆C, MoVN₆C, ReVN₆C, respectively), and the optimal path was * → *N₂ → *NN → *NNH → *NNH₂ → *HNNH₂ → *H₂NNH₂ → *H₂NNH₂–CO₂ → *H₂NNH₂–COOH → *H₂NCONH₂. At the same time, compared with the homonuclear diatomic catalyst V₂N₆C, the heteronuclear diatomic molecular catalyst NbVN₆C had a smaller limiting potential (−0.37 V and −0.59 V), which demonstrated the usefulness of this study.