A patterned carbon nanotube process adopted for an electronic device is described. A negative photoresist layer is coated on a cathode substrate. A mask layer is formed with a carved cavity therein during a development process. A carbon nanotube spray is sprayed thereon to fill the carved cavity with a plurality of carbon nanotubes. The cathode substrate is sintered at a high temperature or in a vacuum to remove the mask layer and part of the carbon nanotubes adhered to the mask layer simultaneously, and to connect the rest of the carbon nanotubes firmly to the cathode conductive layer as an electron emitter layer with high resolution for increasing current density and uniformity of illumination of the electronic device.