A structure of a coplanar gate-cathode of triode CNT-FED and a manufacturing method thereof by Imprint Lithography and ink jet. The structure includes a substrate, a plurality of cathode layers, a plurality of gate extended layers, a plastic dielectric layer, a plurality of dielectric openings, and a plurality of gate electrodes. The plurality of cathode layers and the plurality of gate extended layers are coplanar, and formed on the substrate by Imprint Lithography and the plurality of dielectric openings are made by Imprint Lithography. The gate electrode, made by ink jet or screen print, can be extended through the plastic dielectric layer to the gate extended electrode to feature the coplanar gate-cathode.