The invention discloses a preparation method for a graphite/carbon composite negative electrode material of a lithium ion battery. The preparation method comprises the steps of (1) performing uniform mixing, heating and stirring on graphite, an organic matter and a solvent to form slurry; then performing mixing and kneading on the slurry and heating until the temperature reaches an organic matter softening point temperature or above, performing heat insulation and cooling, and smashing and grinding into powder granules; (2) putting the powder granules into argon atmosphere to be subjected to low-temperature carbonization; (3) performing uniform mixing, heating and stirring on the low-temperature-carbonized material, the organic matter and the solvent to form slurry; then performing mixing and kneading on the slurry and heating until the temperature reaches an organic matter softening point temperature or above, performing heat insulation and cooling, and smashing and grinding into powder granules; and (4) putting the powder granules into the argon atmosphere to be subjected to high-temperature carbonization. According to the preparation method, the temperature of the mixture is heated to reach the organic matter softening point temperature or above for two times, so that the organic matter reaches flowability and can be in contact with graphite more completely, thereby enabling the carbon coating layer, formed after the organic matter is cracked, to be uniform, and further improving the chemical performance of the battery.