Fructan is a very important water soluble carbohydrate.The fructan accumulation in plants can improve stress resistance.This paper introduced some knowledge of fructan and reviewed the effect of fructan on plants' stress tolerance.Some mechanism of freezing tolerance or drought tolerance were expatiated at fructan and osmotic adjustment,fructan and membrane and fructosyltansferase activity.In addition,the gene engineering of improving fructan accumulation and correlated question were reviewed.