Objective. To evaluate the diagnostic criteria for the localization of acquired arteriovenous fistulas （AVFs） by color Doppler flow imaging （CDFI） based on the features of their hemodynamic changes. Methods. The shape and hemodynamic changes of involved vessels which could be helpful to localize the sites of fistulas were studied according to the observation of 10 cases of acquired AVFs. Results. The sites of the fistulas could be shown by two dimensional ultrasonography and color flow imaging in 40%and 80%cases

respectively. In all cases

turbulent high velocity flow was present at the sites of the fistulas

low resistant flow was present in the arteries proximal to the fistulas

and artery like flow was detected in the veins. Conclusion. CDFI was accurate for the localization of acquired AVFs

which were mainly localized by their hemodynamic changes shown by pulse Doppler ultrasound.