The invention relates to a range hood cleaning agent and a preparation method thereof. The cleaning agent comprises the following matters: polyoxyethylene fatty alcohol sodium sulfate AESA, APG (Alkyl Polyglucoside), coconut fatty acid diethanolamide 6501, fatty acid polyoxyethylene ether, triethavolamine, sodium dodecyl sulfate, urea, sodium oleate, high-foaming essence BN-1375, sodium chloride, sodium citrate, anhydrous ethanol, disodium edetate dehydrate EDTA-2Na, essence, and a 5-percent ethylparaben alcoholic solution. The cleaning agent provided by the invention has the characteristics of greenness, high efficiency, sterilization, rust prevention and corrosion inhibition and the like, and is environment-friendly, nontoxic and harmless to environment, high in cost performance and easy to clean, and the range hood cleaning agent can remove stubborn stains on a range hood, and also can effectively remove yellow rust on the surface of the range hood.