Abstract: The research was mainly engaged in the extraction technology of isoflavones from soybean.The optimum extracting conditions were obtained after the study of the effects of ethanol concentration,solvent volume,extracting temperature and time.On the purpose to get the yield of total isoflavones as high as possible,the conditions would include 80% ethanol,at least 18:1 solvent volume to soybean weight,less than 50℃ temperature and not more than an nour time.If genistin was the only wanted product,then the temperature could be increased to 70℃.

Key words: Extraction isoflavones optimum condition