Flower‐like NiCo2S4@biomass‐graded porous carbon (NiCo2S4@BGPC) material was successfully prepared using a simple hydrothermal method and the pseudocapacitive performance was investigated. The results showed that the composite had good capacitive behavior and electrochemical activity due to the structural synergy of the porous carbon and flower‐like material. In this composite, the flower‐like NiCo2S4 had a large contact area with the electrolyte solution, providing many active sites for pseudocapacitive reactions. Meanwhile, the introduction of the porous carbon skeleton further ensured the structural stability of the composite‘s conductive network. In summary, the flower‐like NiCo2S4@BGPC material showed the high specific capacitance of 1322.5 F g−1 at the current density of 1 A g−1 and excellent coulombic efficiency (96.8 % after 1000 cycles at 10 A g−1). However, it has poor cycling stability (77 % of the initial specific capacitance after 1000 cycles at 10 A g−1), which can be attributed to blockage of the pore structure due to volume expansion during the redox process. In two‐electrode system tests, both NiCo2S4@BGPC//NiCo2S4@BGPC symmetrical supercapacitor and NiCo2S4@BGPC//AC asymmetrical supercapacitor showed good capacitance performance and cycling performance, implying potential applications of NiCo2S4@BGPC in commercial electrochemical energy storage.