In summary, we have reported the successful facile synthesis of N-doped thin graphene layer encapsulated Ni-based catalyst. The nitrogen sources had a great effect on the catalyst physical properties and interaction between support and active metal species, which further affected the Ni@N/C catalysts' activity and selectivity for semi-hydrogenation of aromatic alkynes. The optimized Ni@N/C catalyst showed excellent activity and selectivity for semi-hydrogenation of phenylacetylene under mild reaction conditions. More than 10 aromatic alkynes substrates could be transformed to the corresponding alkene product with good to excellent reactivity and selectivity. The graphene encapsulated Ni@N/C catalyst also had good stability and can be applied in the industrially applicable flow reactor, which showed a promising method for ethylene synthesis in industry.