Fe3O4–SnO2–graphene ternary nanocomposite was firstly synthesized by using a gas–liquid interfacial synthesis approach. The as-prepared nanocomposite was characterized by X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. The scanning electron microscopy and transmission electron microscopy characterization results indicate that Fe3O4–SnO2 nanoparticles were successfully deposited onto the surfaces of graphene sheets during the gas–liquid interfacial reaction process. The electrochemical performances were evaluated by using coin-type cells vs. metallic lithium. The Fe3O4–SnO2–graphene nanocomposite exhibits a high reversible specific capacity of 1198mAhg−1 in the 115th cycle at a specific current of 100mAg−1 and good rate capability, even at a high specific current of 2000mAg−1, the reversible capacity is still as high as 521mAhg−1. The good electrochemical performance of the Fe3O4–SnO2–graphene nanocomposite can be attributed to the synergistic effect existing not only between the graphene and metal oxides but also between the Fe3O4 and SnO2.