It　is　very　important　to　develop　non-noble　metal　electrocatalysts　for　oxygen　reduction　reaction　(ORR)　to　replace　noble　metal　electrocatalysts　to　promote　the　large-scale　application　of　fuel　cells.　Here,　three-dimensional　(3D)　N-doped　carbon　supported　MnO　nanoparticles　(MnO/NC)　are　prepared　by　two-step　pyrolysis　method.　The　MnO/NC　performs　excellent　catalytic　activity　comparable　to　20%　Pt/C　for　ORR,　for　instance,　a　positive　onset　potential　(0.92　V),　half-wave　potential　(0.82　V)　and　peak　potential　(0.76　V).　The　MnO/NC　shows　a　strong　tolerance　to　methanol　and　long-term　stability　in　an　alkaline　media.　The　high　ORR　activity　of　MnO/NC　owes　to　its　unique　property　of　fast　electron　transport,　high　specific　surface　areas　and　the　synergistic　effect　between　MnO　and　3D　NC　support.　This　study　projects　an　innovative　strategy　to　construct　electrocatalysts　of　3D　structure　composites,　which　is　expected　to　offer　efficient　non-noble　metal　electrocatalysts　for　ORR.　©　2022　Hydrogen　Energy　Publications　LLC