Abstract: Objective To investigate the antitumor effect of anthocyanidin on lung cancer NCI-H460 cells in vitro and in vivo. Methods Cells proliferation and viability were analyzed by cells count and trypan blue exclusion assay，the inhibitory ratio of NCI-H460 cells was measured by MTT assay, the IC50 value was calculated, cells apoptosis were detected by DNA agarose gel electrophoresis, lung cancer cells NCI-H460 were subcutaneously injected into nude nice to establish cellular transplantation tumor nude mice model，and anthocyanidin were administered to the tumor-bearing nude mice,the kinetics of tumor formation and tumor growth were measured. Results After treatment of anthocyanidin, NCI-H460 cells viability decreased obviously, NCI-H460 cells proliferation were remarkably inhibited by different concentrations of anthocyanidin and the inhibition was both in time-and dose-dependent manner, the IC50 values were 90.8 jug/ml. The typical DNA ladder on agarose gel electrophoresis for analysis of cellular apoptosis were significantly appeared. Anthocyanidin can inhibit the tumor growth of nude mice. Conclusion Anthocyanidin can inhibit NCI-H460 cells proliferation, induce cell apoptosis and inhibit the tumor growth of nude mice.