This paper reported a 13-year-old girl with hereditary megaduodenum.This disease rarely occurs in children. It is a rare familial disease with autosomal dominant transmission characterized by hollow visceral myopathy.It usually presents as recurrent intestinal pseudo-obstruction, clinically manifesting intermittent vomiting and abdominal distention,which can lead to malnutrition and growth retardation. Barium meal examination displays duodenum distention and esophageal manometry reveals esophageal dystonia. The histological features include inflammatory infiltration, marked thinning and fibrosis of the smooth muscle in the intestinal specimens. Diagnosis of the disease depends on the familial history, histological examination, radiographic and esophageal function examinations. Treatment is based on diet and control of bacterial overgrowth. Surgical operation can relieve obstructive symptoms.