Objective To obtain Fe₂O₃ / carbon nano material in a relatively mild environment. Methods Cellulose was hydrothermally treated using nano Fe₂O₄ as catalyst, the product was analyzed using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. Results After 3 h of hydrothermal treatment, Fe₂O₃ / carbon nano material with a size of 150 nm and a rhombic shape was obtained. Conclusion By hydrothermal treating using nano Fe₂O₄ as catalyst, cellulose was carbonized and formed a core-shell nano-sized product, the Fe₂O₄ catalyst was oxidized and became the core of the product.