A method for preparing a silicon-carbon anode material for a lithium ion battery belongs to the field of lithium ion batteries. The method comprises the following steps of: 1) adding SiO2 powder to anaqueous solution of sucrose for stirring and mixing, evaporating the solution to dryness, and drying the solid; 2) grinding the sucrose coated with SiO2, heating to 300-1100 degrees centigrade for sucrose cracking, and then grinding, tableting, and sintering; 3) wrapping the obtained carbon-coated SiO2 tablet with foamed nickel, attaching the fine molybdenum wire to the metal molybdenum wire as acathode, connecting the graphite rod and the stainless steel wire as an anode, and regarding the silver-silver chloride electrode as a reference electrode; 4) after heating CaCl2 to melt, inserting the cathode, the anode and the reference electrode into the molten salt, applying a voltage of 1.5 to 3.0V between the cathode and the anode, electrolyzing the constant cell pressure for 10 to 15 hours, taking the cathode after electrolysis out from the molten salt for cooling, cleaning and drying, so as to obtain a silicon-carbon anode material for a lithium ion battery. The method may be made into a silicon-carbon anode material for a lithium ion battery with excellent performance, and is environmentally friendly, low in cost and simple in operation.