The disclosure relates to a method for making field emission cathode. A microchannel plate is provided. The microchannel plate includes a first surface and a second surface opposite to the first surface. The microchannel plate defines a number of holes extending through the microchannel plate from the first surface to the second surface. The plurality of holes are filled with a carbon nanotube slurry. The carbon nanotube slurry is adhered on inner walls of the plurality of holes. The carbon nanotube slurry in the plurality of holes is solidified.