The invention relates to a polyacrylate-urethane copolymer which has a structural formula shown in the specification of the inveniton, wherein n=3-200, carbon atom number of R1 is less than 25, and R' is polyacrylate. A preparation method comprises the steps of: firstly, preparing polyacrylate with one linear or branched end of Br and the other end of hydroxyl, wherein the polyacrylate has molecular weight of 500-10000 and narrower molecular weight distribution, carrying out nucleophilic substitution on terminal bromine of the polyacrylate by N-methyl ethanolamine to obtain hydroxyl terminated polyacrylate; and then reacting the hydroxyl terminated polyacrylate R(HO)n used as raw materials with isocyanates R1(OCN)n in the presence of a given quantity of solvent or in absence of solvent ata certain temperature under the condition of adding a given quantity of catalyst or no catalyst to prepare the novel polyacrylate-urethane copolymer with molecular weight of above 8000 and molecular main chain containing acrylate and urethane structures. The copolymer has better dissolubility, mechanical behavior, adhesive property and thermostabilization, and has respective advantages of the acrylate and the polyurethane.