The present invention relates to a blackbody radiation source. The blackbody radiation source comprises a blackbody radiation cavity, a black lacquer layer and a plurality of carbon nanotubes. The blackbody radiation cavity comprises an inner surface. The black lacquer layer and the plurality of carbon nanotubes are located on the inner surface. Each carbon nanotube comprises a top end and a bottom end. The bottom end of each carbon nanotube is immersed into the black lacquer layer, and the top end of each carbon nanotube is exposed out from the black lacquer layer. An extending direction of each carbon nanotubes is substantially perpendicular to the inner surface.