In this work, for the first time, carbon self-repairing porous g-C3N4 nanosheets (CPCN-NSs) with high surface area (220.7m2 g−1) are prepared by a solvothermal process coupled with post multistep thermal treatment in air. Then a facile hydrothermal method is developed to synthesize carbon self-repairing porous g-C3N4 nanosheets/NiCo2S4 nanoparticles (CPCN-NSs/NCS-NPs) hybrid composite for supercapacitor electrode. With large surface area as well as ultrathin thickness and porous structure, the as-prepared CPCN-NSs could be served as an excellent scaffold to combine with NiCo2S4 nanoparticles (NCS-NPs), while the NCS-NPs with high conductivity could function as conductive linkers between CPCN-NSs and improve the electrical conductivity of the hybrid composite. Electrochemical characterizations indicate that the as-prepared hybrid composite delivers excellent electrochemical properties, exhibiting a high capacitance (1557Fg−1 at current density of 1Ag−1) and excellent cycling stability (only 7.4% loss after 10000 cycles). These results clearly demonstrate that the combination of CPCN-NSs with NCS-NPs can substantially improve the capacitive performance of materials and ultimately increase the cycling stability of supercapacitor electrode.