〔Abstract〕 Objective To investigate the changes of plasma protein expression profile in hyperhomocysteinemia rats and the protective effect of highly expressed angiopoietin 1 in plasma on endothelial cells. Methods The hyperhomocysteinemia animal model was established. The difference in plasma protein content was analyzed by label-free protein spectroscopy. The effects of homocysteine and angiopoietin 1 on endothelial cell migration and proliferation were detected by wound healing and CCK-8 proliferation assay. Results The results of protein profiling showed that 5 proteins were significantly up-regulated and 17 proteins were significantly down-regulated in the plasma of hyperhomocysteinemia rats, among which angiopoietin 1 was significantly up-regulated. In endothelial cells in the superior mesenteric artery of rats, treatment with 30 or 50 μmol/L homocysteine for 24 h significantly inhibited the migration and proliferation. Angiopoietin 1(600 ng/ml) significantly reduced the migration and proliferation of endothelial cells inhibited by 30 μmol/L homocysteine, but had no significant effect on the migration and proliferation of endothelial cells inhibited by 50 μmol/L homocysteine. Conclusion Hyperhomocysteinemia can significantly affect the protein expression profile in plasma. Angiopoietin 1 in plasma can compensate for the damage of vascular endothelial migration and proliferation function caused by homocysteine in a certain concentration range.