Aurantii Fructus is the dried and immature fruit of Citrus aurantium and its cultivars. To investigate the chemical constituents of Aurantii Fructus, the separation and purification of constituents were performed by column chromatography on silica gel LH-20, HW-40, ODS, PHPLC and PTLC. Fourteen flavonoids, including four flavone glycosides and ten polymethoxyflavones (PMFs) were isolated from the EtOAc fraction and Petroleum ether fraction of Aurantii Fructus and their structures were identified by physicochemical properties and spectral data (NMR and MS) as (2R) -and (2S)-6"-O-acetylprunin (1,2), naringenin-7-O-β-D-glucopyranside (3), 5,7,4'-trihydroxy-8,3'-dimethoxyflavone-3-O-6"-(3-hydroxyl-3-methylglutaroyl)-β-D-glucopyranoside(4), 4'-hydroxy-5,6, 7-trimethoxyflavone (5), natsudaidain (6), nobiletin (7), sinensetin (8), 5,6,7,4'-tetramethoxyflavone (9), 5,7,8,4'-tetramethoxyflavone (10), 3,5,6,7,8,3',4'-heptamethoxyflavone (11), tangeretin (12), 5-demethyl nobiletin (13), and 5-hydroxy-6,7,3', 4'-tetramethoxyflavone (14). Compound 3-5 s were isolated from this plant for the first time and compound 1 was a new one.