The strain QYW-1 isolated from soil displayed the highest activity.Based on single factor experiments used to optimize the medium and cultural conditions,11 important factors influencing enzyme production was selected with Plackett-Burman design.PB design was established to determine the factors mainly influencing the enzyme production in the fermentation medium(konjak powder,pepdone,MgSO4).Further optimum conditions for enzyme production obtained from Box-Behnken design experiments was as follows: konjak powder 26 g/L,peptone 10 g/L,MgSO4 3.8 g/L,NaCl 10 g/L,KCl 6 g/L,NaNO3 6 g/L,K2HPO4 3 g/L,initial pH 6.5.Under the RSM-optimized conditions,the activity of β-mannanase was improved from 115.62 U/mL to 233.86 U/mL.