BACKGROUND Anastomosis of the testicular vein with the superior mesenteric vein rarely causes severe gastrointestinal bleeding. To date, there have been few studies describing its appearance on medical imaging. Here, we present multidetector computed tomography three-dimensional and multiplanar reconstruction (MPR) images of a typical digital subtraction angiography showing proven ectopic bleeding and provide the first review of the image performance. CASE SUMMARY A 68-year-old man who had been rushed to the hospital with a four-day history of melena and fainting underwent multiple esophagogastroduodenoscopy procedures that failed to identify the source of bleeding. We used MPR combined with three-dimensional reconstruction images, and found that the testicular vein had anastomosed with the superior mesenteric vein, and they clustered together in the jejunal vessel wall, which caused severe gastrointestinal bleeding. Digital subtraction angiography confirmed the location of bleeding. After transfusion and embolization therapy, the patient’s condition improved. CONCLUSION Computed tomography-MPR combined with three-dimensional images offers significant value in the localization and qualitative assessment of rare gastrointestinal hemorrhage. The features of multiphase spiral scanning can improve the accuracy of the diagnosis.