BACKGROUND Transplant renal artery stenosis is a relatively frequent vascular complication after transplantation. However, extra-renal pseudo-aneurysms (EPSAs) are rare after transplantation; they can be life-threatening and usually need open surgical repair. We discuss the diagnosis and spontaneous healing of an asymptomatic renal allograft EPSA caused by renal artery anastomotic stenosis, which was diagnosed in a timely manner and managed by conservative treatments. CASE SUMMARY We present a 37-year-old male patient diagnosed with a renal allograft EPSA caused by renal artery anastomotic stenosis due to multiple atherosclerotic plaques with ultrasonographic examination 6 mo post transplantation. The stenosis rate of 90% and the EPSA were verified by computed tomography angiography. The diagnosis was further confirmed with digital subtraction angiography. Percutaneous transluminal angiography was conducted, and a metallic stent was successfully implanted at the stenosed site of the main renal artery trunk. No further intervention for the EPSA was undertaken due to the difficulty of stenting and the risk of bleeding; regular ultrasonographic follow-ups were recommended. The stenosis was significantly relieved immediately after stent implantation and the EPSA was healed spontaneously by completely filling with hypo-echoic thrombosis 8 mo after stenting. CONCLUSION Ultrasonography combined with a high-frequency linear probe can detect vascular complications post renal transplantation at an early stage and improve prognosis.