The purpose of the study is to explore the effect of positional asphyxia on cardiac and pulmonary functions and its role in causing death. respiration, pulmonary artery pressure and cardiac output were measured by inserting the swan-ganz into the pulmonary artery from the femoral vein. Results showed that: (1) the respiration was stable before hanging, getting faster during hanging, and becoming irregular at the terminal stage of hanging; (2) the pulmonary artery pressure increased significantly during and at the terminal stage of hanging as compared with that before hanging; (3) the cardiac output was stable before and during hanging, but decreased significantly at the terminal stage of hanging. It is concluded that hanging may cause respiratory imbalance and hypoxia, resulting in cardiac and pulmonary dysfunction. The death caused by hanging belongs to respiratory death, the characteristic of which is primary respiratory arrest followed by secondary cardiac arrest.