The invention relates to the field of supercapacitor electrode materials, especially to a graphite carbon/metal nitride double-walled nanotube array and a preparation method thereof. The ZnO templateelectrodeposition method is employed to achieve the attachment of a metallic oxide to the surface of a graphite carbon layer and dual-layer coating of a ZnO nanorod by the metal nitride to perform nitrogen treatment and acid pickling for the metallic oxide so as to prepare a graphite carbon/metal nitride composite nanotube array. The preparation method can achieve controllable synthesis of the graphite carbon/metal nitride composite nanotube array and can regulate and control the thickness of each layer of the graphite carbon layer and the metal nitride layer so as to observably improve the conductivity of the metal nitride, improve the transmission speed of electroactive species and improve the performances of electrode materials. The graphite carbon/metal nitride double-walled nanotube array and the preparation method thereof are simple in process, are suitable for large-scale or industrial production, and the prepared graphite carbon/metal nitride composite nanotube array has a superior supercapacitor performance.