Objective: To observe the protective effect of puerarin on cultured human aortic endothelial cells (ECs) injury caused by lipid peroxide. Methods:ECs were treated with diamide to stimulate and faciliate lipid peroxidation. The diamide concentration was 0.1×10-4 and 1.0×10－4mol/L. Then 0.3mg puerarin was added immediately or 0.5h later. Results: Puerarin decreased the LPO and TXA2, then the MTT increased and LDH release decreased. Conclusion: Puerarin reduces the injury of ECs caused by lipid peroxide.It might play an important role in antiatherongenesis.