To study the chemical constituents of the whole lichen of Usnea longissima.The compounds were separated by silica gel, Sephadex LH-20 chromatography and high performance liquid chromatography (HPLC). The structures of the compounds isolated were identified by physico-chemical properties and spectral analysis.Ten compounds were isolated and their structures were identified as (4aR,9bS)-2,6-diactyl-3,4a,7,9-tetrahydroxy-8,9b-dimethyl-1-oxo-1,4,4a, 9b-tetrahydrodibenzo [b,d]furan (1), (+)-usnic acid (2), orcinol (3), 18R-hydroxydihydroalloprotolichensterinic acid (4), 5, 8-epidioxy-5alpha, 8alpha-ergosta-6, 22E-dien-3beta-ol (5), ethyl everninate (6), arabitol(7), apigenin 7-O-beta-D-glucuronide (8), 3-hydroxy-5-methoxy-2-methylbenzoic acid(9), friedelin(10).Compound 1 was a new compound. Compound 8 was isolated from genu Usnea for the first time and compounds 3, 4 and 7 were isolated from U. longissima for the first time.