The effect of different fermentation conditions on the anti-microbial activity of Pleurotus tuber-regium spent culture liquids was determined using Staphylococcus aureus (ATCC6538) as the indicator bacterium. Our data showed that the optimal submerged culture conditions were as follows: temperature, 30 ℃; initial pH of the culture medium, 7.0; culture volume, 80 mL/250 mL culture flask; shaker speed, 160 r/min; and culture period, 6 days. The effect of different fermentation conditions on the anti-microbial activity of Pleurotus tuber-regium spent culture liquids was determined using Staphylococcus aureus (ATCC 6538) as the indicator bacterium. Our data showed that the optimal submerged culture conditions were as follows: temperature, 30 ° C ; initial pH of the culture medium, 7.0; culture volume, 80 mL / 250 mL culture flask; shaker speed, 160 r / min; and culture period, 6 days.