Abstract: Starch grafted oligoguanidine (S-PHMG) was synthesized using epichlorohydrin as the bonding agent. Orthogonal tests were applied to optimize the reaction conditions. Antimicrobial starch-PVA hydrogels were synthesized from chemical crosslinked of starch, PVA and S-PHMG. The reswelling rate, dewatering rate and antimicrobial activity were determined. Results showed that the grafting efficiency could reach 22.15% at the optimal conditions: temperature 40 °C, time 0.5 h, pH=9. The reswelling rates of the hydrogels decreased with the increasing of PVA content, while increased at first and then decreased with the increasing of the crosslinker contents. S-PVA hydrogels exhibited high antimicrobial activities against both E. coli and S. aureus. When w(PHMG)=0.2%, the growth inhibition reached 100%.