Abstract: The chemical constituents of the seeds of Lepidium apetalum Willd. were investigated using chromatographic methods, including Diaion HP-20, Toyopearl HW-40, MCI Gel CHP-20, ODS, silica gel chromatography and semi-preparative-HPLC. Three compounds were isolated and their structures were elucidated by spectral data and physicochemical properties, which were identified as lepidiumamide A (1), cis-desulfoglucotropaeolin (2), trans-desulfoglucotropaeolin (3). Among those, compound 1 is a new phenylacetamide, compound 2 and 3 were isolated from this plant for the first time, and their configurations were also identified for the first time.