Abstract: The development of renewable, low-cost and environmentally friendly electrode materials with fast ion/electron transfer rate and adjustable surface chemistry is an urgent need for the development of current energy storage devices. In recent years, biomass carbon materials have attracted much attention because of their low cost, renewable and good cycling performance, but their low specific capacitance and energy density affect their practical applications. Here, the biomass waste was transformed into carbon materials with good chemical properties, and the transition metal oxide Fe₂O₃ was composite by heteroatom-doped biomass carbon materials, taking advantage of the complementary strengths of Fe₂O₃ and nitrogen doped carbon was used to prepare Fe₂O₃/nitrogen-doped biomass carbon (NBCs) composite materials by one-step carbonization, showing excellent electrochemical performance. The results show that the specific capacitance of Fe₂O₃/NBCs as the negative electrode material is 575 F·g⁻¹ at a current density of 1 A·g⁻¹. At the same time, Fe₂O₃/NBCs-700℃ and NiCoFe-P were used as cathode and cathode materials respectively to assemble asymmetric supercapacitors, achieves an energy density of 33.3 W·h·kg⁻¹ at a power density of 800 W·kg⁻¹. The assembled asymmetric supercapacitors also exhibit excellent cycling stability, maintaining 82.4% capacitance after 3500 cycles. Therefore, Fe₂O₃/NBCs is a promising electrode material for supercapacitors as negative electrode materials.