The invention relates to a water-soluble cleaning agent special for cleaning aluminum alloy, which mainly comprises the following components: 1 to 8 percent of citric acid, 1 to 8 percent of gluconic acid, 3 to 12 percent of potassium carbonate, 2 to 15 percent of sodium xylene sulfonate, 3 to 12 percent of aluminum corrosion inhibitor and the balance of water. The cleaning agent has strong permeation, dispersion, solubilizing and emulsifying functions, has strong capability of cleaning grease and dirt, and has super-strong degreasing, dirt-removing and washing capabilities; the cleaning agent does not contain inorganic ions, is antistatic and easy to rinse, has no residue or little residue, can realize low-bubble cleaning, and can improve the working condition and prevent environment pollution; and the cleaning agent can effectively protect the surface of a cleaned material from being corroded during cleaning.