This paper reported the chemical constituents and anti-inflammatory activities of leaves of Crinum asiaticum var. sinicum,an herb for treatment of rheumatoid arthritis in Xishuangbanna Dai medicine. Thirteen compounds were isolated and purified from C. asiaticum var. sinicum by using column chromatography and identified by chemical and spectral analyses. Their structures were elucidated as 7,4'-dihydroxyflavan( 1),7,4'-dihydroxy-8-methyl-flavan( 2),farrerol( 3),stigmast-4-ene-3β,6β-diol( 4),byzantionoside B...