Abstract: Culture medium and conditions for the fermentation of Agaricus bisporus strain W192 were optimized using the respond surface method.Determined by a single factor test, the optimal carbon source for the mycelial development was cornstarch;the nitrogen source, soymeal;and, the inorganic salts, K2HPO4and MgSO4·7H2O.The fermentation was best carried out in a liquid medium with an initial pH of 6.5in a flask held at 25℃and shaken constantly at 180r·min-1 for 7days.Using the Plackett-Burman design, the conditions for the A.bisporus mycelium biomass culture were evaluated.Cornstarch, soymeal and flask-shaking speed were found to be the most prominent factors that affected the fermentation.Through the respond surface analysis, a regression equation was obtained, and the fermentation conditions optimized as cornstarch at 43.67g·L-1, soymeal at 13.78g·L-1, K2HPO4at 3.0g·L-1, MgSO4·7H2O at 1.0g·L-1, incubation at 25℃, flask-shaking at 200r·min-1, medium initial pH at 6.5, and fermentation for 7days.The resultant A.bisporus mycelium biomass reached a concentration of 2.58g per 100mL, which was 2.35times higher than the orginal conditions.