Fe3O4 nanospheres are synthesized by a solvothermal method with only one step under the assistance of surfactant. Fe3O4/C nanospheres are further fabricated by modifying Fe3O4 nanospheres with glucose as carbon source. The crystalline structure and surface morphology are investigated by a combination of X-ray diffraction, Roman spectroscopy, transmission electron microscopy and scanning electron microscopy. The results suggest that cubic Fe3O4 nanospheres are achieved, with a diameter around 200 nm. After the coating process, uniform carbon layer ~5 nm is formed on the surface of Fe3O4 spheres. The electrochemical performances of prepared Fe3O4 and Fe3O4/C nanospheres as anode materials for lithium-ion batteries are conducted via galvanostatic discharge/charge measurements and cyclic voltammetry. Under a current density of 100 mA g−1, the Fe3O4/C nanospheres exhibit a delithiation capacity of 767.2 mAh g−1 over 100 cycles with excellent capacity retention of 98.2% and improved rate capacities, both of which are better than those of Fe3O4 nanospheres. This work demonstrates that the prepared Fe3O4/C nanospheres can be a promising anode material for lithium ion batteries.