The　low　utilization　of　active　sites　of　metal-organic　framework　(MOF)-derived　nanostructured　carbon　materials　are　considerable　challenges　in　practical　applications.　Here,　we　develop　MOF　(ZIF-8)-derived　N-doped　porous　carbon　(NPC)　nanomaterials　as　high　active　oxygen　reduction　reaction　(ORR)　catalysts　which　are　enhancing　both　the　exposed　active　sites　and　surface　defects　of　NPC　resulting　from　the　enlarged　pore　of　NPC　by　KOH　activation　strategy.　The　experiments　show　that　the　KOH　activation　not　only　enlarged　the　pore　size　of　ZIF-8-derived　NPC　nanomaterials　creating　numerous　mesopores　but　also　generated　abundant　defects　in　NPC　nanomaterials.　The　4　h　KOH-activated　MOF-derived　NPC　(NPC-4)　nanomaterials　show　an　activity　of　0.257　mA　cm(-2)　at　0.9　V　(vs　reversible　hydrogen　electrode),　which　was　almost　10　times　greater　than　that　of　NPC　nanomaterials　(0.0265　mA　cm(-2)).　The　NPC-4　exhibits　a　comparable　ORR　activity,　higher　stability,　and　better　tolerance　to　methanol　compared　with　the　commercial　Pt/C.　The　density　functional　theory　results　show　that　N-doped　carbon　along　with　the　defects　is　more　favorable　for　ORR　compared　with　N-doped　carbon　because　the　presence　of　defects　leads　to　enhanced　O　adsorption　ability　and　promotes　the　ORR　process.