Objective:　Kombucha　was　fermented　with　Saccharomyces　cerevisiae,　Gluconacetobacter　sp　and　Lactobacillus　plantarum　isolated　by　our　lab,　and　its　antimicrobial　action　and　oxidation　resistance　was　studied.　Method:　Saccharomyces　cerevisiae,　Gluconacetobacter　sp　and　Lactobacillus　plantarum　were　mixed　at　the　volume　ratio　of　1:1:1　and　fermerited　to　produce　Kombucha.　The　contents　of　major　components　in　Kombucha,　such　as　acetic　acid,　L-lactic　acid,　citric　acid,　reducing　sugar,　ethanol,　tea　polyphenols,　caffeine,　free　amino-acid　and　protein,　were　determined　to　investigate　the　relationship　between　the　major　components,　antimicrobial　activity　and　antioxidation.　Results:　The　fermentation　broth　of　Kombucha　could　inhibit　six　tested　pathogenic　bacteria　strongly,　including　Epidericha　coli,　Salmonella　enteritidis,　Shigella　dysenteriae,　Listeria　monocytogenes,　Pseudomonas　fluorescens　and　Staphylococcus　aureus.　The　antibacterial　ingredients　of　Kombucha　broth　contained　not　only　tea　polyphenols,　but　also　organic　acids　(mainly　acetic　acid)　and　heat-resistant　materials　produced　during　metabolic　process.　Furthermore,　Kombucha　broth　had　strong　antioxidant　activity.　The　hydroxyl　radical,　DPPH　and　superoxide　anions　scavenging　abilities　of　Kombucha　were　35.00%,　60.07%　and　3.80%,　respectively.　The　reducing　power　was　1.11.　The　antioxidant　activity　was　related　to　the　content　of　tea　polyphenols.　©,　2015,　Chinese　Institute　of　Food　Science　and　Technology.　All　right　reserved.