A polymeric photoinitiator was synthesized from 2-hydroxy-2,methyl-1-phenyl propan-1-one,(HMPP),isophorone diisocyanate(IPDI) and hydroxyethyl acrylat.The resulting product was characterized by infrared spectroscopy and 1H-NMR.The initiating efficiency of product and HMPP to the UV curing system was compared by photo-DSC.The maximal absorbing wavelength of the product was determined by the ultraviolet and visible spectrophotometry,and the related mobility was studied after UV curing.The results indicate that the product is the desired product,the initiating efficiency of 12% synthesized product is close to that of 5% HMPP under the same free radical concentration,while the mobility of the product is less than 10% of HMPP after UV curing.