Oxygen evolution reaction (OER) is a key reaction in water splitting. Single-atom catalysts (SACs) supported on two-dimensional (2D) materials are highly attractive for maximizing their catalytic activity. However, graphene based SACs are primarily bonded with nitrigen and carbon sites, resulting in poor performance for the oxygen evolution reaction (OER). Here, we load single Ni and Fe atove a coupling effect on graphene, which can break the ceiling of SACs to obtain high activity for OER. With the help of single Ni and Fe atoms, the catalysts show low overpotential of 247 mV at the current density 10 mA·cm−2 in an alkaline electrolyte. Specifically, the catalyst exhibits excellent stability at high current density. This work provides a different angle for designing and tuning properties of transition metal electrocatalysts at atomic scale for industrial water electrolysis.