A modified ball-milling-assisted green solid reaction method is provided to prepare Li4Ti5O12/C composite materials with controllable carbon content. Thermal analysis was utilized to investigate the reaction process and the temperature for eliminating carbon. The added carbon and the time for eliminating the carbon can affect the particle size and greatly improve the cycling stability and rate performance. Besides, the particle size can reach similar to 60 nm, the Li4Ti5O12 eliminated carbon at 600 degrees C has similar to 178% higher discharge capacity than that without added carbon after 500 cycles under the same conditions. As for the Li4Ti5O12 with a carbon weight of 10.6%, the second discharge capacity can reach 177.2 and 120.8 mAh g(-1) at 1 and 20 C rates, respectively. Its discharge capacity still remains at 118.3 mAh g(-1) after 500 cycles under various current rates. The results are comparable to those of the reported Li4Ti5O12/PAS composite.