Developing cost-effective and high-efficiency oxygen reduction reaction (ORR) catalysts is imperative for promoting the substantial progress of fuel cells and metal-air batteries. The coordination and geometric engineering of single-atom catalysts (SACs) occurred the promising approach to overcome the thermodynamics and kinetics problems in high-efficiency electrocatalysis. Herein, we rationally constructed atomically dispersed Co atoms on porous N-enriched graphene material C₂N (CoSA-C₂N) for efficient oxygen reduction reaction (ORR). Systematic characterizations demonstrated the active sites for CoSA-C₂N is as identified as coordinatively unsaturated Co-N₂ moiety, which exhibits ORR intrinsic activity. Structurally, the porous N-enriched graphene framework in C₂N could effectively increase the accessibility to the active sites and promote mass transfer rate, contributing to improved ORR kinetics. Consequently, CoSA-C₂N exhibited superior ORR performance in both acidic and alkaline conditions as well as impressive long-term durability. The coordination and geometric engineering of SACs will provide a novel approach to advanced catalysts for energy related applications.