Abstract: To study the composition and antioxidant activity of crude polysaccharide from Ganoderma lucidum fermented wheat bran, antioxidant activities in vitro and components of wheat bran crude polysaccharide were compared before and after Ganoderma lucidum fermentation. The structure of crude polysaccharide from Ganoderma lucidum fermented wheat bran was preliminary studied by HIGH performance liquid chromatography and Fourier transform infrared spectroscopy. Result showed that DPPH radical scavenging, hydroxyl radical scavenging and reducing power of crude polysaccharide from Ganoderma lucidum fermented wheat bran (GWBP) at 4.0 g/L concentration were 91.37%, 95.74% and 0.92, respectively, which were significantly higher than unfermented wheat bran crude polysaccharide (WBP) (P<0.05). The content of flavone, polyphenol and protein in GWBP were 5.41, 12.74 and 206.41 mg/g, respectively, which were significantly higher than those in WBP(P<0.05). GWBP was a pyranose, which was mainly composed of glucose, arabinose, xylose, ribose and so on. The molecular weights of GWBP was 4.172×10³ Da. Liquid fermentation of Ganoderma lucidum improved the antioxidant activity and changed the composition of wheat bran crude polysaccharide. This study laid a foundation for the development of natural antioxidant of Ganoderma lucidum fermented wheat bran crude polysaccharide.