Abstract: The invention provides a composite electrode material for a lithium ion battery. The composite electrode material includes an electrode material and a conductive polymer. The conductive polymer coats the surface of the electrode material with a thickness of several nano-meter level. The electrode material is a positive electrode material or a negative electrode material, and the conductive polymer tends to disperse in an aqueous solution or an organic solution in the presence of a doping and dispersing agent and a dispersing medium. The conductive polymer is selected from poly(3,4-ethylenedioxythiophene) (PEDOT), polyaniline (PANT), or polypyrrole (PPy), the doping and dispersing agent is polystyrene sulfonic acid (PSS), and the dispersing medium is water; or the conductive polymer is polyaniline(emeraldine salt), and the dispersing medium is xylene. A method for preparing the composite electrode material for a lithium ion battery is also provided.