Abstract: The marine bacteria Flavobacteriaceae sp.CZ1127 is abundant in intracellular fucosidase activity. This paper compared various methods for extracting fucosidase,including ultrasonication,chemical reagents,repeated freeze- thawing technique,lysozyme method and osmotic shock,and found that ultrasonication was an favorable one.In order to optimize parameters,the factors of ultrasonication for extracting fucosidase were investigated by response surface methodology,and a second order quadratic equation was finally established. The optimal operating parameters were determined as follows: total ultrasonic time 10.2 min,single ultrasonic time 2 s,intermittent 2 s,and bacterial concentration 20 mg / m L.Under those condition,the yield of fucosidase activity from the bacteria cells was high to( 13285.6 ± 274.3) m U / g.This study established an optimal method for extracting and preparing fucosidase,which would facilitate the further utilization of the enzyme.