Doping engineering is considered an effective way to improve the electrocatalytic water splitting performance of catalysts. In this paper, P-doped Ni3S2/NF was prepared by Ar plasma-assisted chemical vapor deposition, where the P dopant was efficiently introduced into Ni3S2/NF under the assistance of Ar plasma. Meanwhile, numerous vacancies were generated due to plasma bombardment. In the doping process, the P dopants replace the S vacancies, which contributes to the strong bonding between the P dopants and Ni3S2. Due to the synergistic effect of the P dopants and S vacancies, the Sv-Ni3S2-xPx-4 catalyst has low HER and OER overpotentials of 89 mV and 216 mV at 10 mA cm-2, with a lower impedance value and good stability. The present work shows a facile route to introduce dopants and vacancies into catalyst materials for adding active sites, eventually improving their electrocatalytic performance.