In order to optimize the hot air drying process of fresh sweet potato leaves and improve its drying quality, the pretreatment of sweet potato leaves before hot air drying was carried out by ultrasonic and blanching, and different ultrasonic power, temperature, time and proportion of blanching liquid, temperature. The effect of time on chlorophyll, rehydration, chromatic aberration, drying characteristics, energy consumption and microstructure of sweet potato leaves after hot air. The experimental results showed that the optimal ultrasonic conditions are: time 10 min, power 300 W, temperature 40 ℃, the ultrasonic pretreatment of sweet potato leaves has a higher drying efficiency, lower shrinkage rate, and more complete tissue structure. The optimum process conditions were as follow: time 60 s, ratio 21, temperature 80 ℃, the sweet potato leaf rehydration rate, chlorophyll content and color were slightly higher after the blanching treatment, and the texture was tight and uniform, with a high cell opening rate, and a low total energy consumption.