The electrochemical nitric oxide reduction reaction (eNORR) is an efficient method for converting aqueous NO into NH3. The pursuit of innovative electrocatalysts with enhanced activity, selectivity, durability, and cost-effectiveness for NORR remains a research focus. In this study, using particle swarm optimization (PSO) searches, density functional theory (DFT), and the constant-potential method (CPM), we predict two stable two-dimensional FeC4 monolayers, designated as α-FeC4 and β-FeC4, as promising electrocatalysts for the NORR. Our results demonstrate that both α-FeC4 and β-FeC4 monolayers possess intrinsic metallicity with surface Van Hove singularity (SVHS), showing remarkable NORR catalytic performance. Additionally, the substantial disparity in adsorption free energies between NO and H atom at 0 V ensures the high selectivity of these novel FeC4 monolayers toward NORR. These findings not only contribute to the expanding family of two-dimensional transition metal carbides but also provide a new idea for the design of highly efficient NORR electrocatalysts.