The invention discloses a modified alky resin. The modified alky resin is composed of raw materials including, by weight part, 15-18 parts of oleic acid, 1.7-3 parts of benzoic acid, 7-9 parts of binary acid, 6-10 parts of polyols, 1.0-1.5 parts of xylene, 20-30 parts of solvent, 2.5-7.5 parts of acrylic polyoxyethylene epoxy ether, 0.01-0.05 part of tetrabutylammonium bromide, 3.5-5 parts of acrylic acid, 14-30 parts of styrene, 0-10 parts of methyl methacrylate, 0-2 parts of butyl acrylate, 6.5-10 parts of alicyclic acrylate, 1.5-2.0 parts of initiator, 4-7 parts of triethylamine and 65-85 parts of deionized water. The modified alky resin takes the novel alicyclic acrylate as the raw material, which is high in cost efficiency; when the alicyclic acrylate is applied to replacing isobornylacrylate or methyl isobornyl for synthesizing acrylic resin, the prepared resin is significantly reduced in viscosity; when applied to paints, the modified alky resin can significantly improve the water tolerance and the weather resistance of paint films.