To enhance the drying rate and quality of blueberries, the effects of different ultrasonic treatment times (400 W; 10, 20, and 30 min) on the texture, cell wall structure, pectin and cellulase activities, cell wall polysaccharide content, moisture status, and drying characteristics and quality of blueberries were investigated. The results indicated that the hardness values of blueberries treated with ultrasound for 20 and 30 min significantly decreased (4.33 and 3.99 N, respectively); cell walls became wrinkled and loose, and the activities of pectin and cellulase were markedly reduced. Ultrasonic pretreatment facilitated the conversion of chelated and alkali-soluble pectin into water-soluble pectin, increasing its content by 12.64%~34.36%. Furthermore, ultrasonic pretreatment increased the mobility of free water in blueberries. The T23 value increased from 231.88 ms (control group) to 344.56 ms (ultrasonic treatment for 20 min), thereby promoting the outward migration of moisture. Compared with the control group, ultrasonic pretreatment significantly reduced the medium- and short-wave infrared drying time of blueberries by 10.90%~27.24%, and improved the retention of phenolic substances and antioxidant capacity. The optimal ultrasonic pretreatment time was 20 min, resulting in the shortest drying time (22.7 h), a higher retention rate of phenolic compounds, and stronger antioxidant capacity. In conclusion, ultrasonic treatment can effectively improve the drying rate and product quality of blueberries. The results of this study will facilitate future research on blueberry drying.