Hierarchical　N-doped　porous　carbon　has　been　prepared　by　assembling　N-doped　graphene　quantum　dots　(N-GQDs)　onto　a　carbonized　metal-organic　framework　(cMOF-5)　and　used　as　an　electrode　material　for　supercapacitors.　In　this　hierarchical　composite　structure,　cMOF-5　provides　an　effective　cubic　porous　framework　with　a　large　specific　surface　area　and　good　electrical　conductivity,　while　N-GQDs　play　an　important　role　in　enhancing　the　pseudocapacitive　activity　and　improving　the　surface　wettability　of　the　electrode.　Therefore,　the　N-GQD/cMOF-5　composite　electrode　material　exhibits　an　outstanding　specific　capacitance　of　780　F　g(-1)　at　10　mV　s(-1)　in　a　three-electrode　system.　Moreover,　the　composite　electrode　assembled　in　symmetric　supercapacitors　also　displays　a　high　specific　capacitance　of　294.1　F　g(-1)　at　0.5　A　g(-1),　excellent　rate　capacity　and　remarkable　cycling　stability　with　94.1%　of　the　initial　capacitance　retained　after　5000　cycles　at　5　A　g(-1).　When　used　as　the　positive　electrode,　the　N-GQD/cMOF-5//AC　asymmetric　supercapacitor　exhibits　an　energy　density　of　14.4　W　h　kg(-1)　at　a　power　density　of　400.6　W　kg(-1),　while　the　capacitance　retention　after　5000　cycles　reaches　90.1%.　The　current　N-GQD/cMOF-5　composite　electrode　paves　a　feasible　avenue　to　improve　the　capacitive　performances　of　supercapacitors　by　constructing　heteroatom-doped,　hierarchically　porous　carbon　architectures.