Abstract: Pleurotus ostreatus was used as the test material.On the base of single factor experiment,Box-Behnken design in response surface methodology were employed to establish mathematical model for optimization of liquid medium composition of Pleurotus ostreatus while the laccase activity was taken as the response in this study.In order to provide a theoretical basis and reference for the rapid degradation of lignin fiber.The results showed that glucose,yeast paste,Cu²⁺ and inoculation size were main composition for the laccase activity,the optimal composition to produce laccase from Pleurotus ostreatus was as follows glucose 52 g·L^-1,yeast paste 9 g·L^-1,Cu2+1.5 mmol·L^-1,inoculation size 3%.Under the optimized conditions,the laccase activity was 359.12 U·g-1,which agreed closely with the theoretical result of 358.77 U·g^-1 predicted by the developed model.Above results indicate that the response surface methodology was viable for optimizing medium composition in improving laccase activity.