Abstract: The changes of extracting rate of flavonoids and contents of flavors in green tea were compared after processing by dry and wet ultra-fine grinding and extracting by water and ethanol.The optimal extracting conditions of ethanol were confirmed after trial and error:ratio of solid to liquid 1:15,the concentration of ethanol 90%,the extraction temperature 45 ℃,the extraction time 5 h.The extracting rate of flavonoids under the best conditions showed that more flavonoids were extracted after being ultra-fine grond by dry method than wet method,and these two methods are better than normal grinding under cool condition.The finess of flavonoids of green tea are enhanced greatly after being purified through large hole AB-8 ressin.There is no privious changes about the components of flavors after ultra-fine ground.

Key words: green tea, flavonoids, ultra-fine grinding