Aim To study the effect of anti-aging Klotho protein on oxidative damage induced by hydrogen peroxide (H₂O₂) in human umbilical vein endothelial cell (HUVEC) and its mechanism. Methods The oxidative damage model was built by HUVEC treated by H₂O₂. HUVECs were individed into control group, H₂O₂ damage group, different concentrations (1,0, 100 μg/L) Klotho protein groups and serine-threonine protein kinase (AKT) action group. Cell survival rate was detected by methyl thiazolyl tetrazolium assay. Lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD) and reduced glutathione (GSH) content were detected by specific Kit. The content of nitric oxide (NO), endothelin-1 (ET-1), intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and nuclear factor-kappa B (NF-κB) were detected by enzyme-linked immunosorbent assay. SA-beta galactosidase staining was used to detect cell senescence. Reactive oxygen species (ROS) and cell apoptosis were determined by flow cytometry. Expression of Bcl-2, Bax, NF-κB p65 and p-AKT were detected by Western blot. Results Compared with the control group, the survival rate of HUVEC was significantly decreased, the contents of LDH and MDA were significantly increased, the activities of SOD and GSH were significantly decreased, the ET-1, ICAM-1, VCAM-1, NF-κB, ROS, cell senescence rate and apoptosis rate were significantly increased, the expression of Bax protein and phosphorylation level of NF-κB p65 were significantly increased but Bcl-2 protein and p-AKT/AKT decreased, in H₂O₂ damage group (all P＜0.05). In different concentrations of Klotho protein groups, the cell survival rate was gradually increased, the contents of LDH and MDA were gradually decreased, the activities of SOD and GSH were increased, NO content was increased, the ET-1, ICAM-1, VCAM-1, NF-κB, ROS, cell senescence rate and apoptosis rate were gradually decreased, the Bax protein and phosphorylation level of NF-κB p65 were gradually decreased, the Bcl-2 protein and p-AKT/AKT were gradually increased (all P＜0.05). The results of the above indexes in AKT action group were contrary to those of Klotho protein groups. Conclusions Anti-aging Klotho protein can enhance the HUVEC survival rate after H₂O₂ induced oxidative damage, promote cell function and antioxidation, reduce cell inflammatory reaction, aging and apoptosis. It plays roles through inhibiting Bax, NF-κB p65 and promoting Bcl-2, p-AKT/AKT.