The　nitrogen　coordinated　single　cobalt　atoms　embedded　in　carbon　matrix,　i.e.,　Co/N/C　material,　is　cost-efficient　and　free　from　iron-ion　induced　Fenton　reagent,　which　has　been　thus　considered　as　a　promising　candidate　to　replace　the　well-accepted　Pt-based　and　Fe/N/C　materials　for　oxygen　reduction　reaction　(ORR).　Recently,　the　pyrolysis　of　metal-organic　framework　(MOF)　precursors　has　been　investigated　to　achieve　well-defined　Co/N/C　catalysts　with　high　ORR　activity.　However,　the　relationships　among　the　composition/structure　of　MOF　precursor,　the　derived　catalysts,　and　ORR　performance　have　been　rarely　touched　in　specialty,　while　the　regulations　to　achieve　single-atom　Co/N/C　catalysts　derived　from　MOF　are　confusing.　Herein,　we　engineer　several　Co-doped　MOF　(zeolitic　imidazolate　frameworks,　to　be　specific)　precursors　with　different　compositions　and　structures　by　tuning　synthesis　protocols　(e.g.,　ratios,　cobalt　sources,　and　reaction　time)　and　investigate　the　derived　catalysts　and　their　ORR　properties.　The　regulations　to　single-atom　Co/N/C　are　revealed　in　this　work.　The　superior　ORR　activity　and　durability　of　the　optimized　Co/N/C　catalysts　are　revealed　and　attributed　to　the　well-defined　Co-Nx　moieties　and　their　stable　nanostructures.　©　2019　American　Chemical　Society.