Double dilution method was used to determine minimum inhibitory concentration of chitosan,lysozyme and oregano oil against Escherichia coli and Staphyloccocus aureus.Inhibition zone method was used to determine antimicrobial effect of soy protein isolate films enriched with chitosan,lysozyme and oregano oil against E.coli,S.aureus,Saccharomyces cerevisiae and Aspergillus niger.Results indicated that soy protein isolate films enriched with chitosan,lysozyme and oregano oil could inhibit the growth of E.coli,S.aureus,S.cerevisiae and A.niger.The inhibitory effect on E.coli and S.aureus: oregano oil>chitosan>lysozyme.The inhibitory effect on S.cerevisiae: chitosan>oregano oil>lysozyme;the inhibitory effect on A.niger: oregano oil>chitosan>lysozyme.This study showed the films enriched with chitosan,lysozyme and oregano oil have potential to be used as active biodegradable films with strong antimicrobial effects.