To investigate the autopsy characteristics, pathologic type, malfomation and genetic characteristics of complete atrioventricular septal defect (CAVSD). Thirty five cases of CAVSD were collected from Maternal and Child Hospital of Haidian District during Jan.2003 to Jan.2015. Autoptic material, clinical history and chromosome examination were reviewed. Among 35 cases of CAVSD between 18-38 gestational weeks, there were 26 cases with CAVSD A (74.3%, 26/35), 1 case with CAVSD B (2.8%, 1/35) and 8 cases with CAVSD C (22.8%, 8/35). Only CAVSD malformation was seen in 4 cases (11.4%, 4/35). Multiple malformations were seen in 31 cases (88.6%, 31/35). Combined malformations most frequently occurred in cardiovascular, respiratory and locomotor system. Among 15 cases with chromosome examination, chromosome aberrations was found in 13 cases (13/15) and trisomy-21 was found in 11 cases (11/15). CAVSD is a rare disease and CAVSD A is the most common type. CAVSD is usually combined with other malformations and chromosome aberrations.