Tea　residue　contains　high　amount　of　protein,　which　can　be　cost-effectively　extracted　by　alkali.　However,　the　application　of　tea　protein　in　food　industry　was　limited　due　to　its　reaction　with　polyphenols　or　sugars.　In　this　study,　the　physicochemical　properties　and　bio-functionalities　of　the　protein　extract　obtained　from　green　tea　residue　were　determined,　and　the　emulsifying,　foaming　and　antioxidant　properties　were　improved　by　enzymatic　method.　The　results　showed　that　the　protein　content　of　the　extract　was　52%,　and　its　isoelectric　point　(PI)　was　3.6.　The　solubility,　dispersibility,　foaming　and　emulsifying　properties　of　tea　residue　protein　were　positively　correlated　with　the　pH　value　of　the　solution;　when　the　concentration　of　protein　extract　was　80　mg/mL,　the　inhibition　of　psychrophilic　bacteria　and　Pseudomonas　were　98%　and　93%　respectively.　After　pepsin　treatment,　the　foaming　ability　of　protein　extract　was　58.3　mL/g　twice　as　that　of　the　untreated　sample,　and　the　emulsifying　ability　was　100.0　mL/g　four　times　as　that　of　the　untreated　sample.　After　treatment　with　Viscozyme　R　L,　the　foaming　ability　of　tea　residue　protein　increased　to　52.4　mL/g,　the　emulsifying　ability　decreased　to　12.0　mL/g,　while　the　antioxidant　activity　increased　by　about　50%　.　The　results　showed　that　the　protein　extracts　from　tea　residue　and　their　enzymatic　hydrolysates　had　good　functional　properties　and　potential　for　the　application　in　food　industry.　©　2022　Chinese　Institute　of　Food　Science　and　Technology.　All　rights　reserved.