There are three main types of accesses for dialysis: 1. autologous arteriovenous endovascular fistula; 2. artificial blood vessels; 3. catheters. Insufficient dialysis blood flow, the first thing to look at vascular access is which one. 1, if it is a catheter, especially the implantation of long-term catheter with CUFF, the most common cause of insufficient blood flow caused by long-term catheter is thrombosis. If the catheter is implanted inside a large vein, whether there is thrombosis or not, and whether the catheter is attached to the wall or not, can be checked by angiography. If there is stenosis or thrombosis, thrombolytic therapy or even dilation can be performed to improve the flow of the catheter. If this is not possible, the catheter should be removed.2. Endolimbic fistula, which is also the most widely used and recommended type of vascular access. If there is insufficient blood flow, first use ultrasound or DSA to understand the whole blood vessel, whether there is stenosis or thrombosis. If there is stenosis and thrombosis, it can be dilated by balloon to achieve the effect of increasing dialysis blood flow, and if necessary, the autologous arteriovenous endovascular fistula can also be reconstructed.3. In case of artificial blood vessels, if there is insufficient blood flow, it is still necessary to consider whether there is thrombosis. If there is thrombosis, first of all, thrombolysis, if necessary, reconstruction of artificial blood vessels.