Abstract: In order to obtain high efficiency methods of extracting fucoidanase from Flavobacteriaceae sp.CZ1127,this study compared several kinds of methods,and ultrasonic method was selected as the best method. The single factor experiments and response surface methodogy were adopted to search optimalizing conditions of extraction fucoidanase. And a second order quadratic equation was established. Results indicated that the optimalizing conditions of ultrasonic were as follows:ultrasonic power 600 W,bacterial concentration 20 mg/m L,total ultrasonic time 9 min,single ultrasonic time 6 s and internal time 4 s. After optimization,the enzyme activity of fucoidanase by ultrasonic method was improved to(1640.47±84.81) m U/g,and the enzyme activity increased by 56.80%.