Preparation of Ni2P phase with cluster size and high stability is significant for enhancing its catalytic performance. Herein, Ni2P nanoclusters (<1 nm) inlaid in micropore openings on mesoporous ZSM-5 zeolite (MZSM-5) was prepared through citric acid-assisted, two-step impregnation method under the reduction temperature of 400 °C. The facilitation effect of the citric acid and support surface properties on the formation of Ni2P clusters was investigated. The formation of Ni(H2cit)+ complex promotes the dispersion of the Ni precursor on the zeolite surface. After calcination, the free Ni species interact stronger with the acidic hydroxyl groups on MZSM-5 than that with silanol on mesoporous TS-1(MTS-1), Silicalite-1 (MSilicalite-1) and SiO2, facilitating the formation of Ni2P nanoclusters on the MZSM-5 micropore openings after the calcined Ni catalyst was loaded with P species and followed by activation treatment. The obtained Ni2P clusters exhibit higher intrinsic activity (robs = 1.50 mol kg-1 s-1) than MTS- 1, MSilicalite-1 and SiO2 supported Ni2P catalysts (0.80, 0.76, 0.40 mol kg-1 s-1) in the semihydrogenation of phenylacetylene.