Transition-metal-organic frameworks (MOFs) have been regarded as one of the most intriguing electrocatalysts because of its low cost and diversity in functional organic groups and metal centers. Different from the common strategies of tuning the ratio of metal centers in multivariate MOFs, here, ultralow-content Fe2O3 is decorated on the surface of monometallic Ni-MOF-74 based on the fast "phenol-iron (Fe)" surface reaction between Fe2+ and the surface hydroxyl group in Ni-MOF-74. Benefiting from this flexible method, the Fe loading can be finely modulated and thus a series of Fe-decorated Ni-MOF-74 with different Fe contents are prepared. The optimized 0.6 wt % Fe2O3 @Ni-MOF-74 with the Fe loading of 0.6 wt % only needs the overpotential of 264 mV to deliver 10 mA cm(-2), which obviously outperforms Fe-free Ni-MOF-74 (323 mV) and other Fe2O3 @Ni-MOF-74 and is even superior to the commercial IrO2 benchmark (300 mV). X-ray photoelectron spectroscopy results disclose that Fe decoration can obviously modulate the electronic structure of Ni center in Ni-MOF-74, thereby resulting in enhanced oxygen evolution reaction activity. This work opens up a new avenue to fabricate excellent MOF-based electrocatalysts for direct utilization in an electrocatalytic process.