Abstract:The present experiment was conducted to investigate the preparation of chitosan oligosaccharide-zinc（COS-Zn2+）complex and focused primarily on its antibacterial activity.According to Box-Behnken experimental principle，the response surface methodology was performed，with the ratio of COS to Zn2+，pH，reaction temperature，and time as the experimental factors，versus the inhibitory activities against S.aureus and E.coli as response value.The results indicated the influence of preparation factors on antibacterial activity was as follows：the ratio of COS to Zn2+，temperature，time，and pH，respectively.Then，the optimum preparation conditions were obtained，which the value of pH was 5，the reaction time was 2 h，the ratio of COS to Zn2+was 1 ∶1（mass ratio），and the temperature was 45 ℃，respectively.Under these conditions，the inhibition diameters of prepared COS-Zn2+on S.aureus and E.coli were 33.08 mm and 32.23 mm，respectively，which were almost accorded with the predicted data.These results could provide a reference and theoretical basis for the development and application of marine chitosan oligosaccharide resources.