The　research　on　low-cost,　high-performance　non　platinum　group　metal　(PGM)　oxygen　reduction　reaction　(ORR)　catalysts　is　of　great　significance　for　the　rapid　promotion　of　fuel　cells’　practical　applications.　In　this　work,　Mn–N–C　catalyst　with　outstanding　activity　was　prepared　through　using　hydrogel　formed　by　coordination　of　sodium　alginate　(SA)　and　Mn2+　as　the　precursor.　During　the　preparation　process,　g-C3N4　was　added　to　improve　the　surface　area　enrich　the　pore　structure　of　catalysts,　as　well　as　to　function　as　the　nitrogen　source.　Compare　with　commercial　Pt/C　catalyst,　the　optimum　Mn–N–C　catalyst　possesses　extraordinary　ORR　activity　in　alkaline　electrolytes,　with　a　half-wave　potential　(E　　　　　　　　　　　　　　　1/2)　of　0.90　V.　In　addition,　the　Mn–N–C　catalyst　also　displays　exceptional　stability　in　alkaline　and　acidic　electrolytes,　much　superior　to　Pt/C　catalyst.