Abstract: Fruits of strawberry（Fragaria × ananassa‘Toyonaka’）were used to investigate the changes of reactive oxygen and antioxidants during strawberry fruit ripening. The results showed that the production rate of superoxide anion（）increased gradually，the activities of catalase（CAT）and ascorbate peroxidase（APX），and the contents of vitamin E，total polyphenol and total flavonoids decreased significantly during strawberry fruit ripening，which is the main cause of accumulation of reactive oxygen and MDA content. Meanwhile，the main antioxidant of strawberry fruit were vitamin E，total phenols and flavonoid，which were correlated with the antioxidant capacity closely and played an important role to inhibit the production of and H2O2，but not the anthocyanins and ascorbate acid.

Key words: strawberry, fruit, development stage, antioxidant, reactive oxygen