Abstract: In order to have a better comprehensive development and utilization of Indocalamus latifolius leaves,the present research focused on the extraction process of flavonoids and precipitation law of flavonoids and rare earth elements in boiling water from I.latifolius leaves.The results showed that,(1) the optimal extraction process of flavonoids from I.latifolius leaves were extraction temperature of 90 ℃,extraction time of 1.5 h,ethanol concentration of 80%,solidliquid ratio of 1:15 (g/mL).Under the optimal conditions,the maximal extraction rate of total flavonoids was 4.83%.(2) The total content of rare earth elements (REE) in I.latifolius leaves showed a extremely low value of 0.0907 mg/kg,five elements including Pm,Tb,Ho,Tm,Lu were not detected and the content order of other 12 elements was Ce>La>Nd>Y>Sc>Pr>Gd >Sm>Eu>Dy>Er>Yb.(3) In continuous boiling water,flavonoids precipitated during 10-20 min,its content in the boiling liquid reached 0.091 mg/mL.However,the REE precipitation was little,total precipitation amount of all species was only 0.1192 ng/g,the order of precipitation amount was Ce>La>Nd>Y>Sc>Pr >Gd>Eu>Sm>Dy,and Pm,Tb,Ho,Tm,Lu,Er,Yb had no precipitation.The results indicated that,there is a high level of flavonoid content in I.latifolius leaves,its extraction method was simple and showed an obvious precipitation in continues boiling water.Conversely,the REE content in I.latifolius leaves was extremely rare,and precipitated very little in boiling water.

Key words: extraction process, precipitation law, flavonoids, rare earth elements, Indocalamus latifolius