A method for manufacturing a field emission element includes the following steps. The insulating substrate is provided. At least one grid, a first electrode and a second electrode are formed on the insulating substrate. The first and second electrodes are within the grid. The insulating substrate having at least one grid, the first electrode and the second electrode is covered with a carbon nanotube structure. The carbon nanotube structure includes a plurality of carbon nanotubes successively extended from the second electrode to the first electrode. The carbon nanotubes between the first electrode and the second electrode are cut to form a plurality of substantially parallel electron emitters in the at least one grid. One end of each electron emitter is electrically connected to the second electrode and opposite end of each electron emitter faces towards the first electrode.