Fe3O4–graphene nanocomposite was prepared by a gas/liquid interface reaction. The structure and morphology of the Fe3O4–graphene nanocomposite were characterized by X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscopy. The electrochemical performances were evaluated in coin-type cells. Electrochemical tests show that the Fe3O4–22.7wt.% graphene nanocomposite exhibits much higher capacity retention with a large reversible specific capacity of 1048mAhg−1 (99% of the initial reversible specific capacity) at the 90th cycle in comparison with that of the bare Fe3O4 nanoparticles (only 226mAhg−1 at the 34th cycle). The enhanced cycling performance can be attributed to the facts that the graphene sheets distributed between the Fe3O4 nanoparticles can prevent the aggregation of the Fe3O4 nanoparticles, and the Fe3O4–graphene nanocomposite can provide buffering spaces against the volume changes of Fe3O4 nanoparticles during electrochemical cycling.