The airborne ultrasound can be used to remove the moisture at room temperature, which has outstanding advantages for drying heat-sensitive fruits. This paper investigates the microflow phenomenon the airborne ultrasound during the drying process based on the finite element simulation software and experiments. The effect of airborne ultrasound on the microstructure of apple slices and the effect of the ultrasonic power on the moisture content of fruit during the drying process are studied. The result shows that the tissue porosity of apple after airborne ultrasound drying treatment are significantly enlarged, which is beneficial to the diffusion of moisture inside the apple, at the same time, the airborne ultrasound drying can better maintain the microstructure of the sample. Compared with the apple slices without ultrasound treatment, the moisture content of the apple slices after airborne ultrasound treating has been reduced significantly, and the drying rate can rapidly increase in a short time. The above-mentioned results have reference value for understanding the mechanism of airborne ultrasound drying.