Abstract: Objective: To observe the effect of homocysteine (Hcy) on apoptosis and activation of nuclear factor-κB (NF-κB) in ECV-304 cells and investigate the possible mechanism in Hcy induced atherosclerosis. Methods: The apoptosis of ECV-304 cells was detected by PI staining. The expression of Bcl-2 and the location of NF-κB in cells were examined by immunohistochemistry method. The expression of NF-κB in cell nuclear was detected by flow cytometry. Results: Hcy induced apoptosis of ECV-304 cells and the apoptosis index were increased with Hcy concentration and treatment time. When the cells were treated with 10.0 mmol/L Hcy for 24 hours,the number of positive cells in expression of Bcl-2 was increased significantly compared with 1.0,5.0 mmol/L and control group (P < 0.01). In control group,NF-κB was located in cytoplasma,when the cells were incubated with 5 and 10 mmol/L Hcy,NF-κB was transferred into cellular nuclear. After incubation with 5 mmol/L Hcy for 0.5,1,and 2 hours,the expression rate of NF-κB in cell nuclear was (16.76 ±2.55)%, (12.91 ±1.38)% and (14.15 ±1.74)%,respectively. Conclusions: Hcy can induce apoptosis of ECV-304 cells through reducing the expression Bcl-2 in dose-dependent manner. Hcy can activate NF-κB in a concentration-dependent pattern.