Abstract: Objective: The aim of this study was to investigate the protective effects of ethanol extracts of propolis (EEP) on mouse aortic endothelial cells (MAEC) from injury induced by lipopolysaccharide (LPS). Methods: Cell proliferation rate was determined by CCK-8. Then MAEC were divided into the blank group, LPS model group, low-dose (2.5 μg/mL), middle-dose (5 μg/mL), and high-dose (10 μg/mL) groups of EEP. The TNF-α and IL-6 levels were evaluated by ELISA. The expression levels of ICAM-1, VCAM-1 and MCP-1 were measured by Western Blot. Results: Compared with the control group, the cell proliferation rate of MAEC in the LPS group was extremely significant reduced (P<0.001), and the levels of ICAM-1, VCAM-1, MCP-1, TNF-α and IL-6 were extremely significant increased (P<0.001). The cell proliferation rate of EEP groups increased significantly (P<0.05 or P<0.01), and the content of TNF-α, IL-6 and the expression levels of ICAM-1, VCAM-1, and MCP-1 decreased compared with these of LPS group. There were significant differences between each propolis group and LPS group (P<0.01 or P<0.001). Conclusion: EEP could effectively inhibit LPS-induced the expression of inflammatory factors in MAEC, and it has the effect of protecting endothelial cells.