An electron emission device includes a number of first electrodes and a number of second electrodes intersected with each other to define a number of intersections. An electron emission unit is sandwiched between the first electrode and the second electrode at each of the number of intersections, wherein the electron emission unit includes a semiconductor layer and an insulating layer stacked together, the semiconductor layer defines a number of holes, the carbon nanotube layer covers the number of holes, and a portion of the carbon nanotube layer is suspended on the number of holes.