Abstract: Grafting acrylic acid (AA) and urea onto crude konjac glucomannana(KGM) by 60CO-g irradiation to prepare a KGM-AA-urea copolymer and the structural performance was characterized by means of infrared spectroscopy(FTIR)，transmission electron microscope(TEM)，scanning electron microscopy(SEM) and difierential scanning calorimetry(DSC)．The results showed that the optimum reaction mass of urea was 20% and the nitrogen content of product was 8.0%．The product had 146 times absorption of tip water．The free and bounder water content of fully swollen product was 99.73%．Structure analysis showed that the AA grafed with konjac，but urea not．The solid product forms dense network structure and with protuberance on the net surface，which comes from konjac-graft-AA and urea respectively．The product of the solution has two simultaneous microcosmic forms：netted and gelatinous structure．