The response surface methodology was used to optimize microwave-assisted extraction process of polysaccharides from walnut husks. Compared with the ascorbic acid, the preliminary antioxidant activities of the polysaccharides was evaluated by investigated the ·OH, DPPH·, ABTS⁺· free radical scavenging capacity and total antioxidant capacity. The results showed that the optimal conditions were water-feed ratio 25∶1(mL/g), microwave power 750 W, extraction time 8.5 min, extract 2 times. Under these conditions, the yield of polysaccharides was 10.17%. The results of anti-oxidation experiment showed that the walnut husks polysaccharides had some scavenging effects, but not as good as ascorbic acid. The walnut husks polysaccharides scavenged the ·OH， DPPH·， ABTS⁺· free radical as IC₅₀ values of 83 975.520, 628.800 and 694.733 μg/mL, and the FRAP(total antioxidant capacity) were 120.42 μmol/mL.