The preparation of graft polymerization of acrylamide onto starch used in paper packaging material was studied by using ammonium persulfate as initiator. The structures of starch graft polyacrylamide, starch and polyacrylamide were analysed through IR,TG,SEM．Through the analysis of FTIR, it showed the starch was grafted with polyacrylamide; Through the analysis of TG, it showed starch graft polyacrylamide was more stable than polyacrylamide; Through the analysis of SEM, it showed starch graft polyacrylamide was grafted on the superficial of starch and was of reticular structure.