The invention discloses a simple and easy method for directly growing a carbon nano tube array on metal and application, and relates to a method of modification on the surface of the metal and application. The invention aims at solving the problems that an existing carbon nano tube is low in structural strength with a silicon substrate, the carbon nano tube is quite difficultly grown on a metal substrate, a carrier gas used for growing the carbon nano tube on the surface of an alloy is dangerous, a solvent is high in toxicity and the industrialized popularization is unsuitable. The method comprises the following steps of I, carrying out etching treatment, II, introducing nitrogen, and starting a tube furnace; III, injecting mixed liquor of ferrocene and cyclohexane, and reacting for 30min to 120min; IV, closing the tube furnace, and naturally cooling to room temperature under the protection of the nitrogen, so that the metal substrate is obtained, wherein the carbon nano tube array is grown on the surface of the metal substrate. The carbon nano tube array prepared by the simple and easy method has the shear bond strength, which reaches 0.95MPa, with the metal substrate. The invention can be used for obtaining the simple and easy method for directly growing the carbon nano tube array on the metal.