Objective To study the hemodynamics of autologous arteriovenous fistula (AVF) and provide a theoretical basis for reducing its stenosis rate.Methods This study conducted bidirectional fluid-structure interaction simulations on a modified model of AVF. The flow field and wall shear stress (WSS) distribution in internal fistulas at different times and angles were analyzed through the fluid-structure interaction simulation of retrograde and anterograde flow modes for models with different anastomotic angles (30°, 45°, 60°, and 90°). Results In the case of confluence, the area with a WSS value of less than 1 Pa for the model with a concordance angle of 60° is the smallest, and the model with a concordance angle of 45°, 60°, and 90° does not differ much in the size and intensity of the eddy current. In the case of shunting, the area with WSS value less than 1 Pa in the 45° coincidence angle model is the smallest, but the eddy current intensity and eddy current distribution area of the model with a 60° coincidence angle are the smallest, and they are significantly different from the other three angles, and the area with a WSS value of less than 1 Pa in the 60° coincidence angle model is small and the area with a WSS value less than 1 Pa in the 45° coincidence angle model. Conclusions The results show that under both flow modes, the establishment of the fistula with an anastomosis angle of 60° is conducive to reducing the possibility of vascular stenosis in arteriovenous fistula.