Abstract: The longan flesh was taken as the material. Based on the single factor experiments(fermentation agent,juice content,sugar content,fermentation temperature),the process of longan fermented beverage was optimized by orthogonal experiment. And the DPPH scavenging effect and various indexes of longan fermented beverage were tested. The results showed that the optimum fermentation conditions were as follows:The fermented strain chose the fermentation agent of children nutritional yogurt(fermentation agent G),the juice content was 40%(The mass ratio of pure fruit juice to water was 40:60),the sugar content was 9%,and the fermentation temperature was 37 ℃. The sensory score was 88.5 scores. The antioxidant experiment results of longan fermented beverage showed that longan fermented beverage had a good effect of free radical DPPH scavenging,up to 91.4%. The total acid content of longan fermented beverage was 1.41 mL/100 mL,the total sugar content was 152 g/L,the content of formaldehyde was 6.2 mg/L. The content of heavy metal lead and arsenic were not detected,so that it reached the national standard. The contents of E.coli form group,mould,yeast,Salmonella,Shigella,Staphylococcus aureus in microorganism detection indexes were within the requirements of the relevant national standards.