The present invention relates to a surface source blackbody. The plane source blackbody comprises a panel, and a plurality of carbon nanotubes. The panel comprises a first surface and a second surface opposite to the first surface. A carbon nanotube array is located on the first surface of the panel. The carbon nanotube array comprises a plurality of carbon nanotubes. The plurality of carbon nanotubes are substantially perpendicular to the first surface of the panel. The carbon nanotube array has a high emissivity, so the plane source blackbody using the carbon nanotube array as a surface material has a high effective emissivity.