The invention discloses a lithium battery SiCO-Si gradient thin film electrode system. The system comprises a monocrystalline silicon substrate, wherein the monocrystalline silicon substrate is provided with a TiN barrier layer, an Al thin film layer, a SiAlCO thin film layer, a SiCO thin film layer, a SiO[1 / 3] thin film layer and a Si thin film layer from bottom to top in sequence. According to the system, by combining the two potential negative electrode materials, namely SiCO and silicon, through gradient design of specific capacity and mechanical property, the advantages of the two materials are comprehensively realized, and the disadvantages of the two materials are complemented. The thin film system prepared with the magnetic control sputtering method and target materials such as silicon, aluminum and graphite has the advantages of being high in adhesiveness, low in cost, controllable in constituent, low in temperature and the like. Through nanocrystallization of the SiCO surface, lithium diffusion and interface bonding strength are further improved, and the novel thin film electrode system with excellent electrochemical property and interface mechanical property is obtained finally. Furthermore, the method for preparing the SiCO nanometer surface with the chemical corrosion method has the advantages that the process is simple and quick, no expensive instrument is needed, raw materials are rich and cheap, and nanotopography is controllable.