The surface of commercial LiCoO2 was modified by molten salt method. The structure and electrochemical and thermal performances of the MgCl2-treated LiCoO2 were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray photoelectron spectroscopy and galvanostatic cycling. It is found that surface modification improves the structural and thermal stability as well as the rate performance of LiCoO2. These improvements were attributed to the formation of homogeneous solid solution on the surface of the LiCoO2 particle.