To study the constituents from the stems of Aquilaria sinensis.The chemical constituents were isolated by various column chromatographic methods. The structures were identified by spectral analysis including NMR and MS data.Sixteen compounds were isolated and identified as threo-buddlenol C (1), thero-ficusesquilignan A (2), erythro-buddlenol C (3), (+/-) buddlenol D (4), (-) medioresinol (5), (-) pinoresinol (6), 5'-methoxy lariciresinol (7), erythro-guaiacylglycerol-beta-coniferyl ether (8), thero-guaiacylglycerol-beta-coniferyl ether (9), herpetin (10), (+) syringaresinol (11), curuilignan (12), ciwujiatone (13), coniferyl alcohol (14), 3, 4, 5-trimethoxyphenol (15) and cucurbitacin (16).All the compounds, except for 11-13 were obtained from A. sinensis for the first time.