Abstract To investigate the preservative effect of soy protein isolate (SPI) on fresh-cut peaches, fresh-cut peaches were immersed respectively in 0 (double distilled water, control), 10, 20, and 40 g/L SPI solutions before being stored at 4 ℃ for 10 days. The physiological and biochemical indicators associated with the quality and browning of fresh-cut peaches were determined during the storage period. The results showed that the quality of fresh-cut peaches was best maintained by treatment with 20 g/L SPI, which inhibited ethylene release rate, respiratory intensity and bacterial growth. At the end of the storage period, the sample showed increases in the color parameter L* value, firmness and soluble solids content (SSC), lower mass loss rate and decay incidence, and a decrease of 24%, 20% and 17% in the accumulation of reactive oxygen species (ROS), malondialdehyde (MDA) and total phenols, respectively, compared with the control group. Simultaneously, the activities of polyphenol oxidase (PPO), peroxidase (POD) and catalase (CAT) were reduced respectively by 45.5%, 22%, and 44%. These results indicate that the application of 20 g/L SPI can improve the storage quality, enhance the antioxidant capacity, inhibit browning and prolong the storage period of fresh-cut peaches.