Sulforaphane,an isothiocyanate from broccoli,formed from its glucosinolate precursor,glucoraphanin,by the hydrolyzed action of myrosinase,a thioglucosidase enzyme [1].However,the sulforaphane yield from glucoraphanin is low.The effects of grinding on the formation of sulforaphane in broccoli seeds were researched.After grinding,five different particle sizes of broccoli seeds powders were obtained.The water absorption capacity,glucoraphanin content,protein content,the amount of glucose formed myrosinase activity and sulforaphane content were investigated [2-5].The results showed that the particle size was smaller for broccoli seeds,smaller for the water absorption capacity in phosphate buffer and greater for the glucoraphanin content(from 31.33 l mg/g to 40.357mg/g),protein content (from 54.908mg/g to 231.833mg/g),the amount of glucose formed (from78nmol to 198.293nmol) and the sulforaphune content(from 5.846mg/g to 14.037mg/g).But the myrosinase activity was not affected by grinding.The results suggested that the smaller powder may have a better contact with outer water and the extraction yield of effective ingredients could be improved.So the grinding treatment on broccoli seed would be a useful and inexpensive way to improve the sulforaphane yield in broccoli seeds in industry.