The UP-PER-UP blocked copolymer was prepared by the reaction of unsaturated polyester(UP)and polyepoxy resin(PER)under suitable conditions．The modified photosensitive resin was formed after the addition of the active monomers into the copolymer．The UV-cured process of the resin was investigated by means of FTIR spectrum and the properties of the UV-cured coat were characterized in terms of TG／DTA and other analysis．The resuIts indicated that the UV-cured resin showed the advantages of both unsaturated polyester resin and polyepoxy resin．The base-resistant ability

thermostability and surface hardness of the resin were greatly improved．The volume shrinkage of the sample was lowered from 7％ to 0.8％ and the adhesion power on substrate was increased. Thus the applications of unsaturated polyester resin were widely promoted．