Objective To evaluate the maturity of the wrist arteriovenous fistula(AVF) based on the measurement of the radial artery and cephalic vein by duplex. Methods The patients with end stage renal disease who needed the construction of a radiocephalic wrist AVF were enrolled in this study prospectively.The Duplex ultrasound scan was performed. The diameter and the flow of the radial artery and the cephalic vein, and the cephalic vein intimal thickness and the depth of the cephalic vein were measured just before AVF construction and 1, 14, 28, 56 days after AVF construction. 21 patients in Renji hospital from May2014 to December 2014 were enrolled,12 males and 9 females with mean age of 54.3±13.2 years old. Results All cases were followed up for 70 days,and all AVF reached the level of maturation and used for hemodialysis. The ultrasound showed that the increase in the diameter and blood flow rate of the radial artery and the cephalic vein was most dramatic on 1- and 14-day after AVF construction(P0.01), but increase becomed slower on 28 and 56-day after AVF construction(P0.05). As the internal diameter and blood flow rate of the cephalic vein were(5.0±1.0) mm and(1593.7±572.9) ml / min at 28-day after AVF construction,respectively. There was no statistically significant difference in the depth of the cephalic vein from the skin(P0.05). Conclusion The AVF maturity is based on the evaluation of the radial artery and cephalic vein before the construction. The maturity after arteriovenous fistula can be measured by ultrasound.