A method for making a variable-density carbon nanotube film is provided. A drawn carbon nanotube film, including a number of carbon nanotubes aligned along an aligned direction, is prepared. A number of thin regions are formed in the drawn carbon nanotube film along the aligned direction by reducing density of carbon nanotubes in each of the plurality of thin regions. A variable-density carbon nanotube film is provided and includes a number of thin regions and at least one normal region having a density of carbon nanotubes greater than that of the thin regions. The at least one normal region includes a number of carbon nanotubes substantially aligned along an aligned direction. The thin regions are arranged in the form of at least one row extending along the aligned direction.