The graft copolymerization of acrylamide onto konjac glucomannan (KGM) was studied with inverse emulsion polymerization to obtain an effective thickener. The effects of the initiator concentration, emulsifier concentration, comonomer concentration, reaction temperature, and reaction time on the graft copolymerization were investigated. The results showed that the polymerization system retained good stability, and the graft efficiency of the graft copolymerization was almost 95% under optimum conditions. Moreover, both the water solubility and thickening properties of the KGM were improved evidently by grafting with polyacrylamide. (C) 2008 Wiley Periodicals, Inc.