Graft　copolymerization　of　konjac　glucomannan　(KGM)　and　acrylic　acid　was　induced　by　Co-60-gamma　irradiation　at　room　temperature.　The　effects　of　radiation　dose　and　monomer-to-KGM　ratio　on　grafting　yield　and　equilibrium　water　absorbency　were　investigated.　The　KGM-based　superabsorbent　polymer　(KSAP)　could　absorb　water　625　times　of　its　dry　weight　when　the　radiation　dose　was　5.0　kGy　and　monomer-to-KGM　ratio　was　5.　The　structure　of　KSAP　was　characterized　by　FTIR,　XRD,　and　SEM.　KSAP　showed　a　lower　crystallinity　than　KGM.　The　porous　microstructure　of　KSAP　was　revealed　by　SEM.　The　diffusion　mechanism　of　water　in　the　hydrogel　is　consistent　with　the　anomalous　diffusion　model.　Cations,　especially　multivalent　cations,　greatly　reduced　water　absorbency　of　KSAP.　Rising　temperature,　acidic　or　basic　solutions　are　not　favorable　for　the　swelling　of　KSAP.　(C)　2012　Elsevier　Ltd.　All　rights　reserved.