With the polysaccharide content, whiteness and rehydration rate as evaluation indexes, the microwave vacuum drying process of yam was optimized by single factor and quadratic rotation orthogonal experiment, and the functional active components and antioxidant capacity of dried yam were evaluated. The results showed that the regression model established by quadratic rotation orthogonal experiment could reflect the relationship between factors and indexes appropriately. The optimum production conditions were found to be the 3 mm-thick slices were vacuumed with -0.08 MPa at 55 ℃. Under the control of these conditions, the polysaccharide content, whiteness and rehydration rate of dried yam were (4.12±0.08)%, （78.04±0.82） and (223.29±1.31)%, respectively. The IC₅₀ of dried yam scavenging DPPH radical, hydroxyl radical and superoxide anion radical were (18.61±0.11), (19.86±0.15) and (21.06±0.14) mg/mL, respectively. The contents of polyphenols, flavones and allantoin were (0.71±0.05), (1.32±0.04) and (6.86±0.08) mg/g, respectively. Microwave vacuum drying yam had strong antioxidant capacity and good product quality. Microwave vacuum drying technology could reduce the loss of active components and had a good application prospect in the drying of agricultural products.