The invention discloses a silicon-carbon composite material for a lithium ion battery and a preparation method for the silicon-carbon composite material, and belongs to the field of lithium ion batteries. The silicon-carbon composite material is characterized in that carboxymethylcellulose sodium is used as a bonding agent, a liquid phase coating technology is used for silicon-carbon compounding, and a spray drying technology is used for drying granulation to prepare the silicon-carbon composite material with uniform granularity and excellent performance for the lithium ion battery. The silicon-carbon composite material and the preparation method thereof have the advantages that 1, the composite material for the lithium ion battery is prepared through a silicon-carbon compounding technology, and the capacity of the composite material is higher than that of the conventional graphite cathode material, reaches over 500mAh / g, and can meet requirements on the growing of the market of lithium ion batteries; 2, carboxymethylcellulose is used as a bonding agent which can be effectively coated and bonded on the silicon-carbon material to prevent efflorescence caused by silicon during charging and discharging, so that the cycling performance of the silicon-carbon composite material is effectively improved; and 3, the liquid phase coating and spray drying granulation technologies are adopted, so that the silicon-carbon material can be uniformly coated and bonded, has uniform granules, and is small in specific area, and the cycling performance of the silicon-carbon composite material is further improved.