Abstract:The effects of ultra-high pressure, ultra-high pressure time and ultrasonic time on the quality and antioxidant activity of strawberry slices were studied. The results showed that ultra-high pressure combined with ultrasonic pretreatment can significantly improve the quality (color and hardness) of vacuum freeze-dried strawberry slices, and promote the water diffusion during the drying process of strawberry slices. In addition, the antioxidant activity of freeze-dried strawberry slices has been significantly improved after ultra-high pressure combined with ultrasonic pretreatment (P<0.05). The optimal pretreatment conditions are as follows: ultra-high pressure of 100 MPa, ultra-high pressure time of 5 min, and the ultrasonic time of 25 min, the hardness, a* value, anthocyanin content, total phenolics and flavonoids content of strawberry slices were 707.28 g, 31.01, 304.39 mg/kg, 11.60 mg/100 g and 221.41 mg/100 g, respectively.