Objective:To study the role of vascular endothelial growth factor(VEGF) in vein sheath prevention of arterial bypass graft stricture and the efficacies of vein sheath of different diameters. Methods: The vein grafts and their specimens were obtained via animal experiment of sheath intervention. Immunohistochemistry method was used to examine the expression of VEGF and proliferating cell nuclear antigen (PCNA) and the status of nutrient vessel in the specimens,so as to investigate the function of VEGF. Results: Compared with the control group,the vein sheath intervention group had significantly lower VEGF content in the media (P<0.05) and higher content in the adventitia (P<0.05); it also had lower PCNA content in the media (P<0.05) and increased blood vessel density in the adventitia (P<0.05). Conclusion: Vein sheath can effectively increase the distribution of VEGF in the adventitia and decrease its distribution in the media and intima,thus promoting the growth of nutrient blood vessels and decreasing media hyperplasia and re-stenosis.