Oyster mushroom is one of the popular mushrooms for Korean people and it is thus one of the mushrooms thatwere mostly cultivated in Korea in addition to winter and king oyster mushrooms. This study was carried out to compare themedicinal effects of fruiting body of Pleurotus ostreatus extracts. We analyzed comparing antioxidant activity and polyphenolcontents of fruiting body of Pleurotus ostreatus. Firstly, ASI 2099 showed the highest level in hot water. ASI 2122 showed thehighest level in the 70% EtOH and MeOH extraction. Polyphenol contents was measured after extraction with different solvents.polyphenols contents is mostly 8~10 (mg/g) and there is no difference of polyphenols contents depending on the extract solvent.