New method for the synthesis of UV absorber bis-(1,2,2,6,6-tetramethyl-4- piperidinyl)ester phenyl-(3,5-di-tertbutyl -4-hydroxybenzyl)malonitic acid was developed. Bis-(1,2,2,6,6- pentamethyl-4-piperidinyl)ester phenylmalonic acid was synthesized from diethyl phenylmalonate and N-methyl-2,2,6,6-tetramethyl-4-piperidinol catalyzed by micronano-K2CO3 in toluene, and then it reacted with 4-hydroxy-3,5-di-t-butylbenzyl chloride catalyzed by micronano-K2CO3 in ethanol to give the target product. The influence factors were investigated. The optimized overall yield was 80 %. The target product was characterized by means of 1H NMR and 13C NMR.