The effects of sucrose, fructose, glucose and sucrose combined with ultrasonic osmotic pretreatment on the quality and antioxidant activity of vacuum freezing combined with hot air drying strawberry slices were studied. The results showed that the quality, anthocyanin, total phenol, flavonoids, VC content and antioxidant capacity of dried strawberry slices were significantly different after pretreatment (p<0.05). The water content of sucrose-ultrasonic pretreatment was the lowest, and the hardness was the highest. The color of dried strawberry slices with the highest a* was the closest to that of fresh strawberry. The contents of anthocyanins, total phenols and flavonoids in dried strawberry slices were higher than that in fresh samples, but the content of Vc was greatly reduced. The contents of anthocyanins, total phenols and flavonoids in dried strawberry slices pretreated by sucrose combined with ultrasound were 22.68 g/L, 7.52 mg/g and 10.38 mg/g, respectively. The scavenging rate of -OH and DPPH were also higher than that in other groups, but the permeation rate was higher. Ultrasound and Vc content of strawberry slices could not be improved, and the three kinds of sugar treatment could improve the quality of dried strawberry slices, and the sucrose treatment was the best. In conclusion, the quality and antioxidant activity of strawberry slices pretreated by osmosis and sucrose combined with ultrasound were higher, which was suitable for the drying of strawberry slices.