<正>A novel water-soluble macromolecular light stabilizer was synthesized by grafting 2-chloro-4,6-bis- [(2,2,6,6-tetramethylpiperidin-4-yl)amino]-l,3,5-triazine onto polyvinylamine.The intermediate 2- chloro-4,6-bis-[(2,2,6,6-tetramethylpiperidin-4-yl)arnino]-1,3,5-triazine and the obtained macromolecular light stabilizer were characterized by ~1H NMR,HRMS,IR and UV spectroscopy.Cotton fabrics dyed with C.l.Reactive Yellow 145,C.I.Reactive Red 195 and C.I.Reactive Blue 19 were finished with the macromolecular light stabilizer,and the lightfastness of the dyes was tested.The results showed that the lightfastness of the reactive dyes was improved by 0.5-1.0 grade after being finished and the macromolecular light stabilizer exhibited good wash fastness and thermal stability.