Objective　To investigate the anatomical features of the triangle of ductus arteriosus, so as to provide morphologic data for clinical operation in this region.　Methods　Fifty cadavers fixed by formalin were collected randomly. The arterial ligament(AL)、the left vagus nerve and the left recurrent laryngeal nerve(LRLN) were dissected and observed. The angle between the AL and the left pulmonary artery (LPA) was measured, and the data were statistically analyzed.　Results　(1) The AL was located between the aortic arch and LPA, namely in a typical triangle of ductus arteriosus in 47 cadavers, and between LPA and descending aorta in remaining 3 cadavers.  (2) The attachment sites of AL on the aortic arch and LPA varied greatly. According to the different sites, all of the cases could be divided into 6 types. (3) The LRLN originated from the left vagus nerve at the inferior margin of the aortic arch in 36% cases, at the lower 1/3 of the anterior wall of the arch in 30% cases, at the middle 1/3 of the anterior wall of the arch in 14% cases, at the upper 1/3 of the anterior wall of the arch in 14% cases, and at the medial margin of the descending aorta in 6% cases.  (4)The angle between the median axis of the AL and the LPA was（45.08±19.06）° . In 3 cadavers the angle was 0°，and in 2 cadavers was 90°.  (5) The LRLNs hooked around the upper end of the AL and aortic arch in all 50 cadavers.　Conclusion　The results reveal that the morphology of the AL is different from the classical description. The attachment sites of AL on the aortic arch and LPA vary greatly, which makes the relations of the AL to the surrounding structures more complicated. Surgeons should keep the variations in mind to avoid the occurrence of complications during the operation of ductus arteriosus ligation and other operations in this region.