Objective To investigate the proliferation, migration and opoptosis of endothelial cells treated by baicalein(elective inhibition of 12-LOX) in vitro.Methods The morphological changes of cell line ECV-304 from human umbilical vein endothelial cells (HUVEC) and its apoptosis rate in sub-G1 phase were observed with invert,light electron microscope,flow cytometry,MTT assay and migration assay after treatment with or without baicalein at different concentrations.Results After treatment with baicalein at 0.1～100 μM for 1～5 d or up to 6d at 30μM,ECV-304 cells tended to elongate into a shuttle-like sparse appearance,some cells turned into degeneration and necrosis in some degree.All these alteration was in a time-and dose-dependent manner.With flow cytometry,baicalein-treated ECV-304 cells displayed cell cycle inhibition at G0/G1,especially at the 48th h.the cells in sub-G1 phase were significantly increased,and reached its peak at 12 h(10.6%)(P<0.01)after baicalein treatment.The defect area in baicalein treatment group was much larger than that in control group(P<0.001)in same times.Conclusion:baicalein can inhibit the proliferation and migration of endothelial cells,and induce apoptosis, and might also inhibit angiogenesis.