A method for making a polymer solar cell includes placing a carbon nanotube array into a polymer solution. The carbon nanotube array includes a plurality of carbon nanotubes. The polymer solution is cured to form a polymer layer. The polymer layer includes a first polymer surface and a second polymer surface opposite to the first polymer surface. Each of the plurality of carbon nanotubes includes a first carbon nanotube portion and a second carbon nanotube portion, the first carbon nanotube portion is embedded in the polymer layer, and the second carbon nanotube portion is exposed from the polymer layer. The second carbon nanotube portion is tilted on the first polymer surface to form a carbon nanotube layer. A cathode electrode is formed on a surface of the carbon nanotube layer away from the polymer layer. An anode electrode is formed on the second polymer surface.