Objective To determine the optimal harvesting period for blueberry fruits.Methods Seven blueberry cultivars, Bluegold, Homebell, Emerald, Brightwell, Jewelry, Legacy, and O'Neal, were used as research subjects to evaluate the appearance and bioactive components of blueberry fruits at different stages of maturation.Results During maturation, the weight of blueberry fruits expanded from 0.58~1.05 g to 1.40~3.00 g. The content of total phenols and total flavonoids fluctuated considerably, while the total anthocyanins content steadily increased to 71.44~275.33 mg/100 g FW. Fully ripe blueberry fruits demonstrated the highest DPPH and ABTS free radical scavenging capacity and iron ion reduction ability. The composition and content of anthocyanins in the fruits were greatly influenced by the maturation stage. Delphinidin and malvidin were the predominant pigments in fully ripe blueberries, accounting for 50.62%~77.33% of the total pigment content.Conclusion The optimal harvesting period for blueberry fruits is when they are fully ripe, as this is when the bioactive component content is highest, offering the best health benefits. The next best period is during the transition from purple-red to purple-black, when the health benefits are slightly lower than those of fully ripe fruits.