Holiota nameko is an edible mushroom widely cultivated in the northeast of China. The cold water, hot water and ethanol extracts were prepared and their antioxidant properties were studied. At 2 mg/mL, the cold water extract showed a high reducing power of 1.502, whereas those of hot water and ethanol extracts were 0.868 and 0.159. With regard to the scavenging ability on DPPH free radicals, extracts were effective in the order: cold water > hot water > ethanol extracts. EC50 values for chelating ability on ferrous ions for cold water, hot water, and ethanol extracts were 1.461, 0.663, and 11.791 mg/mL, respectively. Based on EC50 values, the water extracts of P. nameko were effective antioxidants.