Abstract: A onepot hydrothermal synthesis method was designed to synthesize SnO2Si/C composites for anode materials of lithiumion battery. The prepared composites were characterized by Xray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM). Results show that the average size of SnO2 particles is 5.3 nm. The addition of carbon restrains the structure change of Si and SnO2 particles as active centers. The uniform dispersion of Si and SnO2 particles in the carbon network enhances the electric contact of composites. The electrochemical characterization shows that the reversible capacity and electrochemical performance of the composites are improved by the carbon network. The composite treated at 400 ℃ under nitrogen, shows reversible capacities of 589 mAh/g after 50 cycles with Coulomb efficiencies close to 99.7%. High specific capacity of 390 mAh/g is still sustained upon cycling at high current density up to 600 mA/g.