Super absorbent polymer was prepared by grafting acrylic acid and acrylamide onto the matrix of oxidized starch,using ammonium persulfate as an initiator and N,N'-methylenebisacrylamide as crosslinking agent.The graft copolymer was characterized by infra-red spectrum and X-ray diffraction analyses.The preparation conditions were optimized.And the results showed that the optimized conditions included 80℃ of the reaction temperature,4∶1 of acrylic acid to acrylamide mass ratio,70% of the neutralization degree of acrylic acid,50% of oxidized starch dosage,0.5% of initiator dosage as well as 0.15% of crosslinking agent dosage.Additionally,the reaction time was 3 h.Under the above optimal conditions,the water absorbency of super absorbent polymer could reach 972.4 g/g.