To investigate the chemical constituents of longan (Dimocarpus longan Lour.) seeds, a ceramides molecular species (compounds 12) were isolated from petroleum ether extract and a cerebroside molecular species (compounds 36) from the w(ethanol)=95% extract on longan seeds by silica gel column chromatography, Their structures were identified on the basis of physical and chemical properties and spectral analysis. compounds 12 and compounds 36 isolated identified as: Rel-(3S,4S,5S)-3-[(2′R)-2′-hydroxydocosylamino]-4-hydroxy-5-[(4′′Z)-tetradecane -4′′ -ene]-2,3,4,5-tetrahydrofuran(1), Rel-(3S,4S,5S)-3-[(2′R)-2′-hydroxytetracosanoyl- amino]-4-hydroxy-5-[(4′′Z)-tetradecane-4′′-ene]-2,3,4,5-tetrahydrofuran(2), 1-O-β-D- glucopyranosyl-(2S,3S,4R,8E)-2-[2′-hydroxylignoceroylamino]-8-octadecene-1,3,4- triol(3), 1-O-β-D-glucopyranosyl-(2S,3S,4R,8Z)-2-[2′-hydroxylignoceroylamino]-8- octadecene-1,3,4-triol(4), 1-O-β-D-glucopyranosyl-(2S,3S,4R,8E)-2-[2′-hydroxyldoc- osylamino]-8-octadecene-1,3,4-triol(5), 1-O-β-D-glucopyranosyl-(2S,3S,4R,8Z)-2-[2′ - hydroxydocosylamino]-8-octadecene-1,3,4-triol(6).