The invention discloses a foam stabilizer and a preparation method thereof, which comprises 0.1kloc-0/0 of cocoamidopropyl amine oxide, 800.2 10 of tween, 520 of palmitic acid, 0. 165438 of stearic acid and 2.9 15 of triethanolamine. 0. 16 part of coconut oil amidopropyl betaine, 0. 16 part of fatty alcohol polyoxyethylene ether ammonium sulfate, 0.1.1disodium diphosphate and water; Heating water, adding disodium ethylenediamine tetraacetate, 1 hydroxyethyl 1, 1 sodium diphosphate, fatty alcohol polyoxyethylene ether ammonium sulfate, cocoamidopropyl betaine, cocoamidopropyl amine oxide, sodium xylene sulfonate and triethanolamine, and stirring to dissolve to obtain a water phase; Heating and melting Tween 80, palmitic acid and stearic acid to obtain an oil phase; Quickly mixing the water phase and the oil phase, stirring and cooling to obtain the foam stabilizer.