A method is provided for fabricating a nano field-effect vacuum tube. The method includes providing a substrate having an insulating layer and a sacrificial layer; and forming a sacrificial line, a source sacrificial layer and a drain sacrificial layer. The method also includes forming a trench in the insulating layer; and forming a dielectric layer on the surface of the sacrificial line. Further, the method includes forming a metal layer on the dielectric layer to fill up the trench, cover the sacrificial line and expose the source sacrificial layer and the drain sacrificial layer; and removing the source sacrificial layer and the drain sacrificial layer. Further, the method also includes removing the sacrificial line to form a through channel; forming an isolation layer on the metal layer; and forming a source region and a drain region on the insulating layer at both ends of the metal layer.