<i>Premna fulva</i> Craib, locally known as "Zhangu" in China, is a kind of traditional medicinal plant. A phytochemical investigation on this plant led to the isolation of a novel flavonoid glycoside along with three known analogues. The chemical structure of the new compound was determined by spectral and chemical analysis as apigenin 8-C-<i>β</i>-D-xylopyranoside (<b>1</b>). Compound <b>1</b> showed weak inhibitory activities <i>in vitro</i> against to four tumor cell lines (HL-60, Bcap37, SMMC7721, and P388) with IC₅₀ values of 12.58, 19.31, 31.02, and 48.19 μg/mL, respectively. The result might be helpful to explain the application of <i>P. fulva</i> in Traditional Chinese Medicine.