Abstract: Fresh-cut apples were treated with 40 kHz, 300 W ultrasound-assisted 0.5 g/L erythorbic acid. With untreated fresh-cut sample as control, the browning index（BI）, activities of polyphenol oxidase（PPO）, peroxidase（POD）, and phenylalanine ammonialyase（PAL）, and contents of polyphenol and malondialdehyde（MDA） were determined to explore the color preservation effect of ultrasound assisted with erythorbic acid（experimental group）treatment on fresh-cut apples. The results showed, that the BI value and activities of PPO and POD of fresh-cut apples in experimental group were significantly lower than those of control group during storage, while the polyphenol content was significantly higher than that of the control group. The PAL activity was significantly lower than the control group at the early and late stage of storage, while the MDA content was significantly lower than the control group at the early stage of storage. Ultrasound-assisted erythorbic acid treatment could effectively inhibit the activity of key enzymes related to browning, and therefore delayed the browning of fresh-cut apples during storage.