The invention provides a preparation method of a composite negative electrode material. The method comprises the following steps: 1, sequentially carrying out ultrasonic cleaning on a carbon material by using acetone, ethanol, hydrochloric acid with the concentration of 10% and distilled water, and immersing the cleaned carbon material in a nitric acid solution with the volume fraction of 10-40% for 10-20 min to obtain a processed carbon material; 2, chemically coppering the processed carbon material obtained in step 1 in a coppering solution at 80-90 DEG C under an ultrasonic stirring condition for 20-30 min to obtain a copper layer coated carbon material; and 3, immersing the copper layer coated carbon material obtained in step 2 in an oxidation solution in a reactor, sealing the reactor, carrying out a oxidation reaction at a high temperature, cooling the obtained reaction product to room temperature, and cleaning and drying the cooled reaction product to prepare the copper oxide layer coated composite negative electrode material. The preparation method of f the composite negative electrode material improves the capacity of the composite anode material and ensures the electrochemical performances of a lithium ion battery.