Abstract: The paper aims to determine the optimal drying condition of Brassica rapa L.. The authors took Brassica rapa L. from Keping, Xinjiang as the test material to carry out tests of different segmentation sizes and different ways of pretreatment (blanching, freezing and cold storage), and of hot air drying, microwave vacuum drying and combined drying. By contrasting the change of moisture content, water activity, color difference, expansion rate, sensory evaluation index of Brassica rapa L. in drying process under different conditions, the optimal drying condition was determine. The results showed that: the optimal segmentation was the film, blanching treatment was 6 min; the effect of cold treatment was better than that of the freezing process; the dehydration rate of combined drying was faster than that of the other two ways, the moisture content and water activity value of combined drying were all low, the color was better, the expansion rate was higher. The optimal drying condition of Brassica rapa L. was following: hot air drying 45℃ microwave vacuum drying 1 kW 10 min, at this time, the moisture content was 7.74%, water activity was 0.19, color difference L*, a*, b* was 69.4, 4.2, 21.0, respectively, the expansion rate was 14.80%, the sensory score was 85. The product is crisp with golden color and sweet taste. The study has a certain guiding significance for production.