Sinus of Valsalva aneurysm (SVA) is considered to be an uncommon cardiac anomaly, carrying a very high rate of mortality. After treatment, the prognosis is excellent. Thus, it is important to make a timely diagnosis and clarify the anatomical details of the SVA. Here, we report a right SVA with dissection into the interventricular septum, with bulging and incomplete rupture into the left outflow tract. The SVA was evaluated using echocardiography (transoesophageal, transthoracic, and three-dimensional echocardiography) and cardiac computed tomography (CT), especially three-dimensional reconstruction, to help us plan the surgical approach. After surgery, the patient's recovery was favorable.