Abstract:A comparative study on extraction rate， chemical composition （content of polysaccharide， protein， polyphenol and galacturonic acid）， antioxidant properties （the ABTS+·scavenging rate， DPPH·scavenging rate and reducing power） of alkaline extracts of nine mushroom（including five medicinal and edible mushrooms and four edible mushrooms were collected from northeast of China） was conducted. The result showed that the yield of the nine mushrooms ranged from 2.6 % to 13.7 %. The content of polysaccharides was range from 321.3 mg/g to 628.4 mg/g， the protein content was range from 36.1 mg/g to 493.9 mg/g， the content of uronic acid was range from 24.6 mg/g to 326.3 mg/g， and the polyphenol content was range from 7.2 mg/g to 24.2 mg/g. Alkaline extracts of Ganoderma lucidum showed the best ABTS+·scavening rate （EC50 value = 0.3 mg/mL） and reducing power, alkaline of Flammlina velutipes showed the best DPPH·scavenging rate （EC50 value = 2.2 mg/ mL）All the mushroom polysaccharide extracts showed a highly strong correlation between the reducing power and the phenols （R2 = 0.942 7） and a moderate correlation between the reducing power and the proteins （R2 =0.527 6）. The correlations between ABTS+·scavenging rate and polyphenol content， and uronic acid content were 0.482 6 and 0.307 3， respectively. The results showed that the antioxidant activity of alkaline extracts of mushroom was mainly related to the polyphenols and proteins.