Abstract: The pH value of medium strongly influenced the enzyme production from corn stover by Trichoderma reesei Rut C-30.During enzyme production,using corn stover as a substrate,without controlling the pH value,higher filter paper activity was obtained and the fermentation time was long.Using buffer to control the pH value,lower filter paper activity was obtained and the fermentation time was stortened greatly.High pH value was beneficial to -glucosidase production and low pH value was advantageous to endoglucanase and cellobiohydralase production.