The invention relates to a method which can improve the field electron emission property of a carbon nanotube film cathode that is prepared by a printing method. The method comprises the following steps of: (1) pretreatment of an aluminum substrate and a carbon nanotube; (2) preparation of carbon nanotube paste, (3) printing of the carbon nanotube paste, (4) sintering treatment of the carbon nanotube printing layer, and (5) post-processing of a carbon nanotube film. By using the method, good mechanical contact is formed between the nanotube and the substrate, thereby further improving the ohmic contact and the thermal conductivity property between the printing carbon nanotube film and the conducting substrate; simultaneously, the method leads the out-of-order carbon nanotube on the substrate to form a carbon nanotube array which is vertical to the surface thereof and form a better nanotube launch point, thereby significantly improving the field emission stability and homogeneity of thenanotube film, reducing the field emission opening field of the carbon nanotube, and increasing the emission current density.