Five phenolic compounds were isolated from the whole plants of Juncus diastrophanthus (Juncaceae) through repeated column chromatography. Their chemical structures were elucidated as methyl 3,5-di-O-caffeoylquinate (1), luteolin-7-O-${eta}$-D-glucopyranoside (2), methyl 4,5-di-O-caffeoylquinate (3), quercetin-3-O-${eta}$-D-arabinopyranoside (4), and methyl 3,4-di-O-caffeoylquinate (5) by spectroscopic techniques. These compounds were isolated for the first time from this plant.