Objective: To investigate the clinical features and improve the diagnosis and treatment of anomalous origin of the left coronary artery from the right coronary sinus with an interarterial course (ALCA-R-IAC) between the ascending aorta and main pulmonary artery in children. Methods: A retrospective analysis of the clinical manifestation, laboratory test, radiological feature, treatment and prognosis were conducted in four female children presented with ALCA-R-IAC in Beijing Children's Hospital from November 2015 to June 2018. Results: The four girls with onset age of 7.5-14.7 years were diagnosed with ALCA-R-IAC by CT coronary angiography (CTCA). Four children presented with exercise-induced syncope and clinical manifestations of acute myocardial infarction including 3 patients with acute left heart failure, 1 cardiogenic shock and 1 cardiac arrest. Nervous system involvement was found in one patient. Troponin I increased significantly to 20.65-50.00 μg/L in the four patients. Electrocardiogram (ECG) developed signs of left main coronary artery involvement. Echocardiography revealed reduced left ventricular ejection fraction (LVEF) of 25%-45% in three children and suspected anomalous origin of the left coronary artery in one child. CTCA showed an anomalous left coronary artery originating from the right coronary sinus, which had an interarterial course between the aorta and pulmonary artery leading to a slim left main coronary trunk. Two children underwent unroofing procedure and the other two children in whom physical activities were restricted received conservative managements. During a regular follow-up period of 12-43 months, all the children survived without recurrent symptoms and had good prognosis. Conclusions: ALCA-R-IAC can present as exercise-related syncope and acute myocardial infarction, even sudden death in children and adolescents. CTCA is helpful to clarify the early diagnosis of ALCA-R-IAC. Surgical intervention is the main treatment for ALCA-R-IAC and strenuous physical activities should be avoided.