1.200 hearts,with the coronary arteries injected with color mass,were used to study the origins of the coronary artery and the accessory coronary artery.Another 300 hearts from the pathological specimens and 30 casts of coronary arteries(with a total of 530)were used to study the distribution of the coronary arteries. 2.For the position of the orifices of the coronary arteries,it is found that:(1) In the longitudinal position,most of the orifices are situated within aortic sinuses,but the left orifice is usually a little higher than the right.(2)In the transverse position, the left orifice is usually situated nearby the midsinal line,while the right is usually somewhat rightward. 3.Accessory coronary artery,which is defined as any branch of coronary artery originates directly from the aorta,is present in 43.5% of the 200 hearts studied.All of them originate from the aortic sinus nearby the right coronary orifice.Almost half of them are distributed to the conus arteriosus and the neighboring anterior wall of right ventricle,the remaining half are distributed to the adipose tissue at the right side of the conus arteriosus and the root of pulmonary artery. 4.Among the 530 specimens observed,it is found that on the diaphragmatic sur- face,the right coronary artery is the predominate one.Type Ⅱ(39.4%)and type Ⅲ (37%)are common types of distribution of coronary arteries.