Abstract: 【Objective】 Effects of different pretreatments combined in hot air and microwave coupled drying of jujube on drying characteristics and quality. 【Methods】 Three different pretreatment techniques: blanching, ethyl oleate combined with pre-freezing and carbon dioxide impregnation were applied to hot-air and microwave coupling drying of jujube. The drying rate, unit energy consumption, quality and aroma components of the products were analyzed. 【Results】 The drying rate of each treatment group was significantly increased, indicating that pretreatment could improve the drying rate of jujube, and the drying rate of ethyl oleate combined with pre-freezing treatment group was the highest ; The color a^* value of each treatment group increased, indicating that pretreatment could improve the color of dried jujube products. The ΔE^* value of the carbon dioxide impregnation treatment group was the smallest, and the color was very similar to that of the fresh ones; The content of active ingredients such as vitamin C, phenols and ketones in the dried jujube samples of the carbon dioxide impregnation treatment group was the highest, and the antioxidant and free radical scavenging ability was high, which had the best nutritional quality ; Microstructure detection indicated that the internal structure of the carbon dioxide impregnation treatment group was porous, which was beneficial to speed up the drying rate and reduce the drying energy consumption; There were significant differences in volatile components among different treatment groups, and the blanching treatment group had more volatile components. 【Conclusion】 Although the drying rate of ethyl oleate combined with pre-freezing treatment group is high, the product quality is poor and the loss of active ingredients is serious. Blanching treatment has more volatile substances, but its drying rate is low. Considering energy saving, high efficiency and product quality, carbon dioxide immersion treatment is a suitable pretreatment method for hot-air and microwave coupled drying of jujube.