Aim To investigate the effect and mechanism of aspirin on human umbilical vein endothelial cells （HUVEC） senescence exposed to high glucose condition. Methods The cultured HUVEC were treated with concentrations of glucose at 5.5, 33 mmol/L and glucose at 33 mmol/L with aspirin at 0.01, 0.1, 1 and 3 mmol/L for 48 h. SA-β-gal staining was used to evaluate senescence. Telomerase activity was detected by PCR-ELISA. Cell cycle and the level of reactive oxygen species （ROS） were detected by flow cytometry. Results Endothelial cells exhibited the characteristic of senescence, increased the number of β-gal positive cells, decreased telomerase activity significantly, enhanced the proportion of HUVEC in the G0/G1 phase and reduced that in the S phase and increased the level of ROS after exposure to high glucose （33 mmol/L, P<0.05）. All these phenomena were reversed by 0.01, 0.1 and 1 mmol/L aspirin remarkably （P<0.05）. However, there was no significant difference between 3 mmol/L aspirin group and high glucose group. Conclusions 0.01, 0.1 and 1 mmol/L aspirin delay endothelial cell senescence exposed to high glucose. This positive effect may be associated with decreasing oxidative stress.