Lycium barbarum polysaccharide (LBP), extracted from Lycium barbarum that is a kind of traditional Chinese herb, is found to have anticancer activity. In this study, the effect of LBP on the proliferation rate, cell cycle distribution and apoptosis in the human hepatoma QGY7703 cell line were investigated. The effects of this compound were also tested on the concentration of calcium in cells. LBP treatment caused inhibition of QGY7703 cell growth with cycle arrest in S phase and apoptosis induction. The amount of RNA in cells and the concentration of intracellular Ca2+ were increased. Moreover, the distribution of calcium in cells was changed. Taken together, the study suggests that the induction of cell cycle arrest and the increase of intracellular calcium in apoptotic system may participate in the antiproliferative activity of LBP in QGY7703 cells.