The incidence of extracorporeal circulation accidents is low. in 2014 the incidence of extracorporeal circulation accidents was only 2.6 per 1,000, while in about 25% of hospitalized patients experience some injury caused by an accident. Medical treatment itself is a flawed act, and accidents are inevitable with the best instrumentation, experience, and perfect treatment strategy. Extracorporeal circulation is the worst area for medical accidents, as it is the most life-threatening treatment measure. To reduce extracorporeal circulation accidents and injuries, it is very important for perfusionists to be licensed, and two perfusionists must be involved in every extracorporeal circulation procedure. The risks of extracorporeal circulation are only part of the risks of cardiac surgery. Cardiac surgery also has anesthesia risks, surgical operation risks, postoperative resuscitation, rehabilitation risks, and so on. Cardiac surgery is divided into congenital heart disease, coronary heart disease, rheumatic heart disease, and large vessel lesions, and each good cardiac surgeon is only good at one part of them. Currently, in large hospitals and some specialized cardiovascular hospitals, the mortality rate of cardiac surgery is below 2% and close to 1%. Choosing a surgeon with a high volume of cardiac surgery and a specialty to perform cardiac surgery can further improve the success rate of the surgery and reduce the risk.