Abstract: Intestinal duplication is a rare congenital disease. Its clinical manifestations are nonspecific, and preoperative diagnosis is difficult. Gastrointestinal angiography, ultrasound, and CT are often used to detect this disease. A case of small intestinal duplication can be diagnosed through ⁹⁹Tc^mO₄⁻ imaging. The advantages of this radionuclide imaging have been emphasized in literature. It can be used to diagnose intestinal duplication and help identify causes of lower gastrointestinal bleeding in children.