Single coronary artery (SCA) is a rare congenital malformation. In this case report, we present the admission of a young man to our department for the establishment of an antihypertensive program. The physical examination and lab tests did not reveal any obvious abnormalities. However, we found an absent left coronary ostium and a normal right coronary artery (RCA), which branched off the left coronary artery to supply the left heart. Further investigations including coronary computed tomography angiography (CCTA) and coronary angiography ruled out coronary heart disease. Transthoracic echocardiography revealed severe left ventricular dysfunction. Through the implementation of effective drug therapy, the blood pressure met the recommended standard and the young man remained in good clinical condition during follow-up.