In the present study, the CoSb3 powder was prepared by solvothermal route for the first time and the particle size of the as-prepared powder is in nanoscale. The electrochemical performances of the nanosized CoSb3 were characterized by galvanostatic charge and discharge cycling, cyclic voltammogram (CV) and electrochemical impedance spectroscopy (EIS). The electrochemical lithiation and delithiation mechanism of CoSb3 compound was investigated by ex situ XRD (X-ray diffraction) technique. The large reversible capacity and good cycling stability of nanosized CoSb3 suggest that it stands as a promising anode material for secondary Li-ion batteries.