A new phenolic glycoside, 1-O-[beta-D-glucopyranoyl-(1-->6)-beta-D-glucopyranosyl]-3,4,5-trimethoxyphenol, named prismaconnatoside (1), together with one known phenolic glycoside (2) and four aspruloside type iridoid glycosides (3-6) were isolated from the roots of Prismatomeris connata. Their structures were determined by spectroscopic and spectrometric methods. Based on the results, along with those from other studies, iridoids were suggested to be chemical markers to distinguish between P. connata and P. tetrandra, two species that are confused in traditional Chinese medicine.