Abstract: To study the chemical constituents from the roots of Vaccinium fragile and their bioactivity.The chemical constituents were isolated and purified by chromatographic techniques, and identified by NMR, MS spectroscopic analyses.In the 60% ethanol extract, two compounds were isolated and identified as cinnamtannin B1 (1), 2-ethylene-3, 5, 6-trimethyl-4-phenol-1-O--D-xylopyranosyl-(16)--D-glucopyranoside (2), respectively.Compared with the vehicle control, compound 1 can significantly inhibit the acetic acid-induced writhing pain in mice.Compound 2 is isolated from the genus Vaccinium for the first time, compound 1 is first obtained from this plant.It is the first report of the analgesic activity of compounds 1 and 2.