Abstract： Objective To investigate the roles and working procedures of medical teams aboard the hospital ship. Methods Three hundred and seventy five sailors were divided into five batches, each consisting of 75 sailors. In accordance with the basic features of combat casualties at sea, the sailors acted as mock casualties sustaining various injuries. The medical teams of the hospital ship were made up of 50 people, who were divided into 7 teams, I.e. The command team, the triage team, the surgical team, the treatment team, the medical care teams (2 teams) and the logistical team. Through practical training on medical support aboard the hospital ship, an analysis was made on casualties sustained during war at sea and medical people available aboard the hospital ship. Proper distribution of combat medical posts, roles and working procedures of medical personnel at various levels were also described and analyzed. Results Analysis showed that quality of medical care aboard the hospital ship varied considerably, with a good quality rate ranging in a numeric order from 22% , 46% , 58% , 82% and 94% respectively for the 5 medical trainings at sea.Conclusions Through training on the roles and working procedures, medical teams aboard the hospital ship substantially improved their capability in emergency response, overall eoordination and quality of medical care at various levels.