Abstract: Bamboo-based hard carbon materials for sodium ion battery anodes were prepared by a two-step method of pre-carbonization combined with high-temperature reforming using bamboo as raw material. The influence of reforming temperature on the structure of hard carbon, and the structure-activity relationship between structure and sodium storage performance were explored. The research results showed that the high refining temperature could shrink the pores to form a closed pore structure and reduce the specific surface area, as well as led to a decrease in the layer spacing. When the refining temperature was 1 400 ℃, the specific surface area of the sample BHC-1400 was 9.2 m²/g, and the layer spacing was 0.375 nm. Its rich closed-pore structure and reasonable interlayer spacing were beneficial to the improvement of sodium storage capacity. BHC-1400 exhibited a reversible sodium storage capacity up to 364.3 mAh/g at a current density of 50 mA/g and an initial Coulomb efficiency of 81.2% as an anode material for sodium-ion batteries. Capacity retention rate keeps at 85% after 5 000 cycles of charging and discharging.