To study the phenolic constituents from the dry stem of Juncus effusus L. , the constituents were isolated by normal-phase and reverse-phase silica gel column chromatography from the EtOAc extract. Their structures were elucidated by spectral analysis. Six phenolic constituents were purified and identified as 7-carboxy-2-hydroxy-1-methyl-5-vinyl-9,10-dihydrophenanthrene (1) , 2,3-isopylidene-1-O-ferulic acid glyceride ( 2 ) , ( 2S )-2, 3-isopylidene-1-0-p-coumaroyl glyceride (3 ) , dehydroeffusal ( 4 ) , p-hydroxybenzaldehyde (5) and luteolin-5,3'-dimethyl ether (6). Compounds 1 and 2 are new compounds. Compounds 5 and 6 were isolated from Juncaceae plant for the first time. 13C NMR data of compound 6 were reported for the first time.