Spontaneous pseudoaneurysm of the superior mesenteric artery (SMA) is rare. However, it may have severe life-threatening complications such as ruptures or thrombosis. Our patient has developed a pseudoaneurysm, which was being misdiagnosed as superior mesenteric vein dissection by the computed tomography angio-graphy. The pseudoaneurysm is revealed from branches of the SMA with no specific causes and is being treated by endovascular embolization after emergency exploratory laparotomy.