The invention provides a method for preparing an ethylene diamine tetraacetic acid (EDTA) modified carbon paste carbon nano tube membrane electrode, relates to a method for preparing a carbon nano tube membrane electrode, and aims to solve the technical problems that in the conventional method for preparing the carbon nano tube membrane electrode, the modifying layer of the electrode tube is not fixed, and the advancing amount of the copper wires is difficult to control. The method comprises the following steps of: 1, preparation of an electrode tube; 2, preparation of an EDTA modified carbon paste electrode: grinding graphite powder and EDTA in a mortar, adding a hydrophobic adhesive, uniformly stirring the mixture to obtain the carbon paste, and filling the carbon paste in an electrode tube shell by extrusion; and 3, preparation of an EDTA modified carbon paste carbon nano tube membrane electrode. According to the method, the EDTA modified carbon paste carbon nano tube membrane electrode has high anti-interference capability and high electrode stability, and is quite suitable for analyzing and monitoring copper ions in water-steam systems of thermal equipment of power plants, refinery plants and chemical enterprises, and moreover, the advancing amount of the copper wires can be accurately controlled.