Development of the electrochemical water splitting is impeded by the important yet sluggish half-reaction of oxygen evolution reaction (OER). Atomic dispersion of Fe-Co species represents a new type of potential materials for OER. However, it is still highly challenging to exploit facile and efficient methods for such synthesis. Herein, we have developed a rapid mechanical ball milling approach to synthesize highly-dispersed Fe/Co/N on graphene as OER electrocatalyst, which displays high OER performance with over potential of 288 mV at 10 mA cm(-2) and no obvious decay after 9 h of continuous operation at 10 mA cm(-2). This excellent electrocatalytic performance originates from atomic-scale accessible iron, cobalt and nitrogen electrocatalytic sites and highly conductive graphene. These results suggest feasibility of this facile and efficient ball milling method in synthesis of other electrocatalysts for various applications. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.