A method for making a heater is provided. A support and a flexible substrate are provided. The flexible substrate is fixed on a surface of the support. A carbon nanotube film is drawn from a carbon nanotube array. One end of the carbon nanotube film is attached on the flexible substrate. The carbon nanotube film is wrapped around the support by whirling the support to form a carbon nanotube layer. The carbon nanotube layer includes a plurality of carbon nanotubes aligned in a first direction. The flexible substrate is heated to a temperature of about 80° C. to about 120° C. The flexible substrate is then shrunk along the first direction. A plurality of electrodes are electrically connected with the carbon nanotube layer.