The invention discloses a thermoplastic acrylic resin. The thermoplastic acrylic resin is characterized by comprising the raw materials in parts by weight: 25-40 parts of methyl methacrylate, 20-30 parts of butyl acrylate, 15-30 parts of alkyl-containing acrylic monomer, 2-5 parts of hydroxyethyl acrylate, 1-2 parts of acrylic acid, and 1-2 parts of initiator, wherein the alkyl-containing acrylic monomer is one of isobornyl methacrylate, isobornyl acrylate, cyclohexyl methacrylate, tert-butyl cyclohexyl methacrylate and 3,3,5-trimethyl cyclohexyl methacrylate, or the compound thereof. The invention further provides a preparation method for the thermoplastic acrylic resin. The thermoplastic acrylic resin disclosed by the invention is high in Tg value, low in viscosity, good in application property, levelling property and dryness, full and bright in appearance, not easy to generate indentations, low in VOC (volatile organic compounds) discharge, and environment-friendly.