The changes in physicochemical properties of probiotic fermented beverage during processing and fermentation were studied.The results showed that the number of viable cells in the mango juice after fermentation was 2.13×107 cfu/mL,and the POD enzyme,PPO enzyme and PME enzyme were inactivated under the optimal conditions.After fermentation of mango juice,the antioxidant activity and the nutrient content increased.The content of protein,total sugar,water,vitamin C,and the soluble dietary fiber increased by 92.97%,47.32%,1.66%,27.37%,and 13.24%,respectively.The titratable acid increased by 1 time,but the reducing sugar content decreased by 10.84%.The total phenolic content in fermented mango juice increased by 13.24% compared with fresh mango juice.The results of ultra-high performance liquid chromatography (UPLC) showed that the content of gallic acid,p-hydroxybenzoic acid and mangiferin decreased after fermentation,and the content of quercetin and its derivatives and gallic acid glycosides increased significantly.After fermentation,the ratio of sugar to acid of mango juice was 62.91±0.72,making the fermented mango juice have sweet,sour,harmonious taste and high quality.The color of the fermented mango juice is softer and the graininess is increased,but the dispersion is more uniform and the state is more stable.