Eagle tea, the leaf of Litsea coreana Levl. var. lanuginosa (Migo) Yang et. P. H. Huang (family Lauraceae), is a well-known traditional beverage in south of China. Since first recorded in compendium of materia medica（bencao gangmu）, Eagle tea had been used for antitussive, antiasthmatic prescriptions, detoxification, detumescence, refreshment, improving eyesight, promoting blood circulation therapy, relief heatstroke for hundreds years. Furthermore, as routine beverage, Eagle tea is widely used in southwest (Guizhou province, Yunnan province, Sichuan province) and east (Anhui province) of China. In recent years, Eagle tea had attracted more attention because of its beneficial health effects and special taste. However, the study of pharmacological activities was limited to total extracts and total flavonoids of Eagle tea, and bioactive compound of Eagle tea was still unclear. Thus, the objective of present study was to investigate the chemical components in Eagle tea and develop a valid method for quality control of Eagle tea. In addition, antioxidants in Eagle tea was also investigated in present study. The dissertation consists of four chapters. Chapter I reviewed the chemical and pharmacological of Eagle tea. Chapter Ⅱ showed the chemical study of flavonoids in Eagle tea. The separation of Eagle tea extract was carried out by using silica gel column, pre-HPLC and sephadex chromatography. Five compounds were isolated from Eagle tea extract and their structures were identified as hyperin (quercetin--3-O-β-D-galactopyranoside), isoquercitrin (quercetin-3-O-β-D -glucopyranoside), kaempferol-3-O-β-D-galactopyranoside, quercitrin (quercetin-3-O--L-rhamnopyranoside), astragalin (kaempferol-3-O-β-D -glucopyranoside) by MS, UV and NMR data. The quercitrin was firstly isolated from Eagle tea. Chapter III A pressurized liquid extraction and high performance liquid chromatography coupled with diode array detection method was developed for simultaneous determination of seven flavonoids (hyperin, isoquercitrin, kaempferol-3-O-β-D-galactopyranoside, quercitrin, astragalin, quercetin and kaempferol) in Eagle tea. This method is help to control the quality of eagle 澳門大學碩士學位論文 IX tea. In Chapter IV, online HPLC–DAD-MS couple with 2,2’-Azinobis (3-ethylbenzthiazolinesulfonic acid) diammonium salt (ABTS) assay were estabilished for investigating antioxidant activity of flavonoids in Eagle tea, and hyperin, isoquercitrin, quercitrin, quercetin and kaempferol showed the activity. Key words: Eagle tea; Flavonoids; Chemical isolation; HPLC; Quality control; ABTS; Antioxidants.