Objective · To observe the vascular structure before autogenous arteriovenous fistula (AVF) construction in patients with end-stage renal disease (ESRD) and analyze the risk factors of the pre-existing venous neointimal hyperplasia. Methods · The 8 vein samples were screened from 20 ESRD patients at their first time of the AVF construction (non-stenosis group), and the other 8 vein samples were screened from 15 ESRD patients at their at least second time of the AVF repair operation (stenosis group). Sections were prepared and stained with hematoxylin & eosin (H-E) or Masson’s trichrome for observation. The intimal thickness was measured by the cellSens software, and its correlation with patients’ renal function, calcium-phosphorus metabolism, iron metabolism and inflammatory reaction in the non-stenosis group were analyzed. Results · In the non-stenosis group, there were varying degrees of intimal hyperplasia in 5 (62.5%) cases, loss of endothelial cell layer in 3 (37.5%) cases, and vascular wall replacement by collagenous with atrophy or loss of muscle layer in 5 (62.5%) cases. In the stenosis group, almost all vein samples showed general thickening of the wall and 2 (25.0%) totally lost the muscle layer. Avg It of those two groups were statistically significant (P<0.01). In the non-stenosis group, both of average I/M thickness and average I/M area were negatively related to glomerular filtration rate (GFR) (P<0.05) and positively related to serum phosphorus and calcium-phosphorus product (P<0.05). Conclusion · Some apparently normal vein of ESRD patients showed varying degrees of intimal hyperplasia before AVF construction. The intimal hyperplasia had a remarkable correlation with GFR or calcium-phosphorus metabolism. Early intervention of the intimal hyperplasia prior to AVF construction may be a new prevention and control means.