The development of effective, stable, and inexpensive electrocatalysts through oxygen evolution reaction (OER) is important but also very difficult. Anion defects are used to control the active sites of electrocatalysts. In this study, we persent an easy NaBH₄ reduction strategy for engineering a novel Fe-doped nickel phosphide material with phosphorus vacancies, (i.e., Fe-Ni₂P (P_V)) for OER. Interestingly, this easy NaBH₄ reduction tactic can fulfill defects engineering (i.e., P vacancies). The P vacancies can adjust the electronic structures of electrocatalyst for OER. Fe-Ni₂P (P_V) has outstanding OER performance, e.g., a lower overpotential (290 mV at 10 mA cm⁻²), smaller Tafel slope (41.15 mV dec^-1), and excellent durability (93.5% for 12 h) under alkaline condition. This work indicates the detailed structural changes of NaBH₄ reduction treated-engineered materials and improves understanding of the structure-effect relationship of high performance OER electrocatalyst.