Objective To investigate the effect of quercetin on proliferation and apoptosis of human lung cancer cellline A- 549 in vitro. Methods The cultured A- 549 cells were treated with different concentrations of quercetin, and cellproliferation and apoptosis were detected by MTT and flow cytometry, respectively. The morphological changes of the apoptotic cells were observed by invert microscopy, transmission electron microscopy and Heochst33258 fluorescence staining. The expression of survivin was analyzed by Western blot. Results After treatment of quercetin for 24 h the proliferation of A- 549 cells was inhibited in a dose- dependent manner, and cells were arrested at the G2/M phase. The apoptosis rates of quercetin treatment groups (15, 30, 60μmol/L) were(7.24±1.73)%, (12.57±2.72)%and (26.02±1.67)%, respectively, significantly higher than that of control group [(2.67±2.32)%, P<0.01]. Apoptosis or necrosis of A- 549 cells were morphological y observed after quercetin treatment for 24h. The expression of survivin protein in quercetin- treated A- 549 cells was decreased in a dose- dependent manner. Conclusion Quercetin can inhibit proliferation and induce apoptosis of human lung cancer A- 549 cells, which is associated with cellcycle ar-rest and down- regulation of survivin expression.