Objective To study the chemical constituents from the flowers of Arundina graminifolia and to find its bioactive compounds.Methods The compounds were extracted by 95% alcohol and isolated by column chromatography on silica gel and Sephadex LH-20.The structures were identified by spectroscopic analysis (1H NMR,13CNMR and EIMS).Results Eight compounds were obtained and identified as (1) 7-hydroxy-2,4-dimethoxy-9,10-dihydrophenanthrene;(2)coelonin;(3)4,7-dihydroxy-2-methoxy-9,10-dihydro-phenanthrene;(4)ephemeranthoquinone;(5)densiflorol B;(6)4-(3-hydroxyphenyl)-2-butanone;(7) stigmasterol,(8) β-sitosterol.Conclusion Among them,compound 6 is discovered for the first time from the plant.