A carbon nanotube yarn includes a number of carbon nanotube yarn strings bound together, and each of the carbon nanotube yarn strings includes a number of carbon nanotube bundles that are joined end to end by van der Waals attractive force, and each of the carbon nanotube bundles includes a number of carbon nanotubes substantially parallel to each other. A method for making the carbon nanotube yarn includes soaking the at least one carbon nanotube yarn string drawn out from a carbon nanotube array in an organic solvent to shrink it and then collecting it.