Garlic have many bioactive components,which is challenge for making full use of them.Present work was that extracting garlic fructan with alliinase was investigated by modulating pH,fming,selecting absorbance and so on.The results showed that alliinase was precipitated at pH 4 and obtained by centrifugation.The garlic fructan also was gotten by purifying with macroporous resin.The extraction ratio is 85%,the activity connect of alliinase is 72U/mg,and the recovery of alliinase activity is 62%.