Polymer electrolyte membrane water electrolysis (PEMWE) is regarded as one of the most important cornerstone technologies in the upcoming hydrogen society. However, one of the major problems it encounters is its slow oxygen evolution kinetics, which necessitates the use of large amounts of precious metal catalysts to ensure a satisfactory reaction rate. Herein, we have prepared a series of RuOx with porous structures and ultrahigh Ru utilization toward the oxygen evolution reaction. All porous samples exhibit an enhanced catalytic performance compared with commercial RuOx. Particularly, for the RuOx-350 sample, the overpotential to reach 10 mA cm-2 is as low as 225 mV. It has obvious advantages among all reported pure RuO2-based catalysts. Here, a new strategy was raised to construct efficient RuO2 electrocatalysts with outstanding activity and stability for water electrolysis technology.