Abstract:The thermostability，pH stability，and antibacterial and antioxidant activities of violacein were determined.Further，violacein was used to prepare the polyvinyl alcohol/violacein（PVA/Vio）composite film with the solution of PVA.The film was then used to preserve grass carp and the preservation effect and shelf-life were evaluated.The results showed that violacein had stable activity within the ranges of pH1-10 and 0℃-80℃.The minimum inhibitory concentrations of violacein for Staphylococcus aureus，Streptococcus pyogenes，Listeria monocytogenes，and Bacillus cereus were 3.13，6.25，12.50 mg/L and 6.25 mg/L，respectively.The IC50of violacein for scavenging ABTS+and DPPH free radicals were 1.64 mg/L and 14.72 mg/L，respectively.The violacein of 12.50 mg/L showed the total reduction ability of 88.49 μmol/L.In addition，the PVA/Vio film has good antioxidant and antibacterial activities.Compared with PVA film and polyethylene film，the PVA/Vio film improved the preservation effect on the grass carp stored at 4 ℃，inhibited the increases in total viable count and thiobarbituric acid reactive substances，and prolonged the shelf-life by about 4 days.