Using graphene as a support and 2-methylimidazole as a nitrogen source, nitrogen-doped carbon (N-C) supports were synthesized via ball milling, followed by loading with nickel nanoparticles (Ni NPs) to construct nitrogen-doped Ni-based catalysts (Ni/N-C). The structural composition and microscopic morphology of Ni/N-C were characterized through SEM, TEM, XRD, XPS, Raman spectroscopy, and H?-TPR. These catalysts were employed for the hydrogenation of acetylene to produce ethylene. Further, density functional theory (DFT) calculations quantified their catalytic activity. Results indicate that nitrogen doping enhances metal-support interactions, exposing additional active sites on the catalyst surface; the Ni nanoparticles exhibited an average particle size of 10.40 nm, effectively suppressing agglomeration and leaching. Nitrogen doping not only improved the catalyst’s oxidative stability but also optimized the electronic structure of the active metal Ni. Catalytic tests demonstrated complete conversion of acetylene at 200?°C, with ethylene selectivity maintained at 95% within the 200~210?°C range, representing a 33% improvement over undoped Ni/C systems. DFT calculations confirmed that nitrogen incorporation lowered the activation energy barriers for the two-step hydrogenation of acetylene to ethylene by 1.49 eV and 1.89 eV, respectively, increasing the energy barrier difference between main and side reactions and thus favoring the formation of the desired product, ethylene.