The invention relates to a preparation method of highly wear-resistant polyurethane resin for synthetic leather. The preparation method comprises the following steps: (I) heating and reacting polydiols, diisocyanate, dihydric alcohol chain extender, antioxidant, and catalyst in a solvent to prepare a prepolymer, wherein the diisocyanate is excessive; (II) adding terminator allyl alcohol for end group blocking to obtain macromolecules with -C=C structure-containing end group; (III) adding free radical polymerized initiator, function end group-containing micromolecular alkene for polymerization reaction; and (IV) adding free radical reaction terminator for terminating reaction, and regulating the viscosity to obtain the final product. The -C=C structure-containing end group is introduced into the tail end of the prepolymer, and then functionalized group-containing monomer is introduced into the tail end of the prepolymer, thereby functionally modifying the polyurethane in molecular level so as to achieve the purpose of improving the physical property of the polyurethane resin and enabling the produced synthetic leather to have better low-temperature, normal-temperature wear resistance property.