Hetematom-doped　hierarchically　porous　carbon　is　attractive　electrode　material　for　supercapacitors.　However,　it　still　remains　a　great　challenge　to　develop　a　high-performance　supercapacitor　electrode　with　efficient　preparation　strategy.　Herein,　we　report　a　N,O-codoped　hierarchically　porous　carbon　(NOHPC)　prepared　through　one-step　carbonization/in-situ　doping/activation　process　by　using　natural　diatomite　as　template　and　polydopamine　as　precursor.　The　as-prepared　NOHPC　possesses　synergistic　advantages　of　abundant　redox-active　N,O　dopants,　large　effective　specific　surface　area　and　hierarchically　porous　(micropores,　mesopores　and　macropores)　structure.　Benefiting　from　such　advantages,　the　NOHPC　electrode　exhibits　an　extremely　high　specific　capacitance　of　436.0　F　g(-1)　at　0.625　A　g(-1)　in　H2SO4　electrolyte.　The　as-assembled　supercapacitor　in　H2SO4　electrolyte　also　yields　high　specific　capacitance　(328.3　F　g(-1)　at　0.625　A　g(-1)),　excellent　rate　performance　(74.8%　capacitance　retention,　0.625-25　A　g(-1))　and　superb　cycling　stability　(93.9%,　10,000　cycles).　Besides,　the　corresponding　device　in　Na2SO4　electrolyte　can　present　an　enhanced　energy　density　of　23.4　Wh　kg(-1)　at　the　power　density　of　358.8　W　kg(-1)　(1　A　g(-1))　and　still　maintain　15.0　Wh　kg(-1)　at　the　power　density　of　8357.8　W　kg(-1)　(25　A　g(-1)).　The　outstanding　electrochemical　performance　and　the　efficient　preparation　process　of　NOHPC　make　it　a　promising　widely　applied　electrode　material　for　supercapacitor.