【Abstract】 Objective To compare and analyze the difference in the expression of TGF beta1/Smad3 in the primary and secondary arteriovenous fistula surgery in maintenance hemodialysis, and explore their clinical significance. Methods The venous specimens and related clinical parameters of the patients who underwent primary (group A) and secondary (group B) arteriovenous fistulas in our hospital from June 2017 to June 2019 were collected. The patients were followed up for 6 months, and the outcomes of arteriovenous fistulas (mature or immature) of the two groups were recorded. The patients were divided into fistula mature group and fistula immature group. He staining and immunohistochemical staining for TGFβ1 and Smad 3 were performed. The expression of TGFβ1/Smad3 and the related clinical parameters were compared between the two groups. The related parameters of the mature group and the immature group were further analyzed to explore the risk factors for the maturation of internal fistula. Results There were 48 cases in group A and 46 cases in group B. compared with group A, the proportion of female and diabetes mellitus in group B was significantly increased (P＜005). In group B, there were significant intimal hyperplasia, smooth muscle cell hyperplasia and vascular lumen stenosis. In group B, the expression of TGFβ1 and Smad3 were significantly increased. Compared with the mature fistula group, the proportion of female and diabetes in the immature fistula group was higher, the diameter of radial artery and cephalic vein was smaller, and the expression of TGFβ1 and Smad 3 in intima was significantly increased (P＜005). Multivariate correlation analysis showed that the increased expression of TGFβ1 and Smad3 in intima was positively correlated with the immature fistula (P＜005). Conclusion The expressions of TGFβ1 and Smad3 in intima of vein were significantly increased in re fistula group and immature fistula group, and the expressions of TGFβ1 and Smad3 in intima of vein were positively correlated with the immature fistula. It is suggested that the excessive activation of TGFβ1/Smad3 signaling pathway in the intima of arteriovenous fistula is not conducive to the formation of arteriovenous fistula. Female, diabetes mellitus, diameter of radial artery and cephalic vein are risk factors for fistula maturation in hemodialysis patients.