The invention relates to a polymer which is prepared by the steps of reacting epoxy(methyl)acrylate, allyl glycidyl ether or [ethylnenoxy(methyl)] ethylene oxide with ammonia or primary amine to obtain a mixture of monomeric compounds; reacting the above mixture of the monomeric compounds with at least one of acrylic acid, vinyl alcohol, vinyl acetate, acrylamide, methacrylic acid and methacrylamide to obtain an intermediate polymer; and reacting the intermediate polymer with dithiocar-bamate. The invention also relates to an application method of the polymer.