The invention provides a copper base material cleaning agent. The copper base material cleaning agent is composed of, by weight, 0.05%-2% of organic acid activators, 0.05%-1% of a nonionic surface activator, 0.01%-0.6% of an anion surface activator, 0.005%-0.2% of an antioxidant, 0.005%-0.2% of a chelating agent, and the balance deionized water. In addition, the invention discloses a preparation method of the copper base material cleaning agent. The copper base material cleaning agent is free of attenuation and controlling over the attenuation, can be directly used, does not contain heavy metal, is free of residues and can meet the processing requirements for copper before hot dipping; the surface of a copper base material processed by the cleaning agent is pure and is free of dark spots, oil contaminations, fingerprints and the like; accessories obtained after tinplating are free of exposed copper, dark spots and other defects, and the surfaces of the accessories are smooth.