The invention belongs to the field of 
electrochemistry and energy material, and discloses a preparation method of a 
biomass derivative carbon material used for 
sodium-
ion batteries. According to the preparation method, soybean is taken as a 
biomass source, KOH is taken as an activator, high temperature calcining is carried out so as to obtain the porous 
biomass derivative carbon material. Soybeanis a 
natural product, is abundant in sources, is high in 
protein content, contains a large amount of 
nitrogen element, and is capable of forming a natural 
nitrogen doped carbon material; the nitrogendoped carbon material can be used for providing Na<+> with sufficient 
sodium embedding vacancies, providing substantial fake 
capacitance in 
sodium-
ion battery charging and discharging process, and increasing battery specific capacity; and in addition, 
nitrogen element 
doping is capable of improving material 
conductivity, and increasing iron transmission efficiency; KOH activation is capable of increasing porous structure specific surface area further, it is beneficial for 
electrolyte infiltration, and increasing of 
ion and 
electron transmission efficiency. The biomass derivative carbon material possesses the above advantages, so that when the biomass derivative carbon material is taken as a sodium ion 
anode material, relatively high reversible specific capacity and excellent circulation stability are achieved.