Cayratia trifolia (L) Domin berry is a source of high biological activity compounds, having the capacity of antioxidation, reducing the growth of tumors, and is used as a medicinal ingredient as well as a good material source for alcoholic wine. This study aims to investigate the total polyphenol and antioxidant capacity of Cayratia trifoliaextract before and after fermentation, contributing to the interest of developing the raw materials for fermented fruit wine, a very popular product. The analysis results of 53 samples of Cayratia trifolia berries collected in 13 cities and provinces in the Mekong River Delta showed that: the contents of reducing sugars in Cayratia trifolia berries could reach from 0.22 to 0.96 mg/100 ml, and the total polyphenol and the antioxidant capacity were obtained at 0.47 to 1.54 mg GAE/ml and 16.61 to 82.86%, respectively. In the tests of wine making from the extract of Cayratia trifolia berries, which were collected at Ca Mau and Kien Giang provinces, using thermotolerant yeast Saccharomyces cerevisiae HG1.3, the results indicated that the total polyphenol and the antioxidant capacity of Cayratia trifolia extracts before and after fermentation were stable since the difference was not significant at 5% (p<0.05). In the Cayratia trifolia extract before fermentation, the polyphenol concentrations were 53 and 66 mg GAE/100 ml, and the antioxidant capacities were 44.9 and 54.7%, respectively. In the Cayratia trifoliaextract after fermentation, polyphenol concentrations were 61 and 60 mg GAE/100 ml, and the antioxidant capacities were 51.4 and 57.3%, respectively.