Fuel　cells　operated　with　a　reformate　fuel　such　as　methanol　are　promising　power　systems　for　portable　electronic　devices　due　to　their　high　safety,　high　energy　density　and　low　pollutant　emissions.　However,　several　critical　issues　including　methanol　crossover　effect,　CO-tolerance　electrode　and　efficient　oxygen　reduction　electrocatalyst　with　low　or　non-platinum　usage　have　to　be　addressed　before　the　direct　methanol　fuel　cells　(DMFCs)　become　commercially　available　for　industrial　application.　Here,　we　report　a　highly　active　and　selective　Mg−Co　dual-site　oxygen　reduction　reaction　(ORR)　single　atom　catalyst　(SAC)　with　porous　N-doped　carbon　as　the　substrate.　The　catalyst　exhibits　a　commercial　Pt/C-comparable　half-wave　potential　of　0.806　V　(versus　the　reversible　hydrogen　electrode)　in　acid　media　with　good　stability.　Furthermore,　practical　DMFCs　test　achieves　a　peak　power　density　of　over　200　mW　cm−2　that　far　exceeds　that　of　commercial　Pt/C　counterpart　(82　mW　cm−2).　Particularly,　the　Mg−Co　DMFC　system　runs　over　10　h　with　negligible　current　loss　under　10　M　concentration　methanol　work　condition.　Experimental　results　and　theoretical　calculations　reveal　that　the　N　atom　coordinated　by　Mg　and　Co　atom　exhibits　an　unconventional　d-band-ditto　localized　p-band　and　can　promote　the　dissociation　of　the　key　intermediate　*OOH　into　*O　and　*OH,　which　accounts　for　the　near　unity　selective　4e−　ORR　reaction　pathway　and　enhanced　ORR　activity.　In　contrast,　the　N　atom　in　SAC–Co　remains　inert　in　the　absorption　and　desorption　of　*OOH　and　*OH.　This　local　coordination　environment　regulation　strategy　around　active　sites　may　promote　rational　design　of　high-performance　and　durable　fuel　cell　cathode　electrocatalysts.　©　2023