The contents of titratable acids, flavonoids, total phenols, and total anthocyanins in the extracts of mature blueberry fruits from 6 varieties of fresh blueberry fruits in the main production areas of Yunnan Province were compared by physiological and biochemical methods, and their antioxidant activities in vitro were evaluated. The results showed that Biloxi had the highest titratable acid content, flavonoids content, total phenol content and total anthocyanin content, which were 47.4%, 111.81%, 121.16% and 2556.50% higher than Sharpblue. The results of antioxidant activity evaluation in vitro showed that Biloxi had the strongest scavenging capacity for DPPH free radical.When the concentration was 0.8 mg/mL, the scavenging capacity was 56.8%. The scavenging capacity of ABTS⁺was the best, and the scavenging capacity was 90.4% when the concentration was 1.0 mg/mL. The scavenging capacity of OH-is the highest. The content of flavonoids, total phenols and total anthocyanins in 6 varieties of blueberry fruits were positively correlated with the clearance rates of DPPH free radical, ABTS+free radical and OH-free radical,and the correlation reached an extremely significant level（P<0.01）. In summary, Biloxi have higher titratable acid content, stronger antioxidant capacity than other 5 varieties, and it's suitable for comprehensive processing and high value utilization.