The polysaccharide was extracted from Ledum, and the content and characteristics of polysaccharide from Ledum were investigated by IR, UV spectra, thermal analysis (TG) and X-ray diffraction (XRD). The results from IR and UV spectra showed that the extracts containing the typical group of polysaccharide. It was noted that the content of Ledum polysaccharide was 69.95%. In addition, the antioxidant activity containing total reductive ability, scavenging ability for DPPH radical (DPPH·), hydroxyl radical (·OH) and superoxide anion radical (·O-2) were investigated. The results showed that the EC₅₀ for scavenging DPPH·, ·O-2, ·OH were 0.52, 1.41, 1.71 mg/mL, which means that the polysaccharide from Ledum possessed a notable antioxidant activity. Moreover, the antioxidant ability was close to BHT and increased with the growth of the content of polysaccharide. The results of thermal stability from thermal analysis (TG) showed that the chemical decomposition of polysaccharide from Ledum was occurred at 190 ℃. The crystallinity of polysaccharide from Ledum was 3.6%, the low degree of crystallinity resulted in a poor molecular rigidity.