Abstract: Aim ：To investigate the mechanism of anti-proliferation，anti-migration and anti-angiogenic effects of tanshinone IIA. Methods ：In this study，MTT，2-D/3-D migration，tube formation，PCR，chick embryo chorioallantoic membrane (CAM) were used to evaluate the anti-proliferation，anti-migration and anti-angiogenic effects of tanshinone IIA. Results ：Tanshinone IIA significantly inhibited the proliferation of human breast cancer line MDA-MB-435 with an IC₅₀ of 21 nmol/mL.And it is showed that breast cancer cells migration was effectively prevented by tanshinone IIA at 5 and 6 nmol/mL in a wound healing assay and a transwell migration assay.In addition，tanshinone IIA inhibited the tube formation of newborn cattle aortic endothelial cells(NCAECs) after 2 h co-incubation with MDA-MB-435.These effects were not due to the inhibition of NCAECs proliferation；because tanshinone IIA non-selectively inhibited NCAECs growth with an IC₅₀ of 124 nmol/mL.Tanshinone IIA showed dose-dependent inhibitory effects on mRNA expression of VEGF and two transcription factors (HIF-1α/c-Myc). Tashinone IIA was also found to inhibit angiogenic in vivo in the CAM assay. Conclusion ：These results suggest that tanshinone IIA may exert its anti-proliferation，anti-migration and anti-angiogenic effects through down-regulating two transcription factors and VEGF.These novel anti-proliferations，anti-migrations，anti-angiogenic activities of tanshinone IIA are likely to contribute to its cancer chemopreventive and therapeutic potential，especially in the treatment of breast cancer.