Coupling transition metal oxides with nanocarbonaceous materials is an effective approach to construct high-efficiency anode materials for lithium-ion batteries (LIBs). In the present study, we demonstrate a novel in-situ redox strategy for facile and cost-effective synthesis of Fe3O4/reduced graphene oxide (Fe3O4/rGO) composites as LIBs anodes. Fe3O4/rGO composites are facilely obtained through redox reaction between highly-oxidized graphene oxide and ferrous salt under basic atmosphere, followed by stabilization treatment ranging from 5 min to 5 h. Well crystallized Fe3O4 nanoparticles with diameters of 10–30 nm are tightly and homogeneously anchored on the flexible graphene substrate. Owing to the distinctive composite nanostructure, including strong integration, homogeneous distribution and surface modification effect, the as-prepared Fe3O4/rGO composites exhibit superior electrochemical lithium-storage performance, especially at high current densities. The Fe3O4/rGO-2h composite delivers a remarkable reversible capacity of 1024 mA h g−1 at the current density of 1000 mA g−1, and retains 584 mA h g−1 at 5000 mA g−1 even after 450 cycles. It is believed that the study will provide a feasible strategy to facilely produce transition metal oxide/carbon composite electrodes with superior electrochemical performance for LIBs.