A method for making a carbon nanotube sponge requires a carbon nanotube source being obtained and an organic solvent being added. The organic solvent is ultrasonically agitated to form a flocculent structure. The flocculent structure is washed by water and a carbon nanotube sponge preform obtained by freeze-drying the flocculent structure in a vacuum. Finally, the carbon nanotube sponge itself is obtained by depositing a carbon layer on the carbon nanotube sponge preform. A carbon nanotube sponge obtained by above method is also presented.