A field emission electron source includes a linear carbon nanotube structure, an insulating layer and at least one conductive ring. The linear carbon nanotube structure has a first end and a second end. The insulating layer is located on outer surface of the linear carbon nanotube structure. The first conductive ring includes a first ring face 1301 and a second ring face, an end surface of the linear carbon nanotube structure, and the first ring face are coplanar.