In Ancient Europe，the ship doctors had existed，but they had not played an important role. When coming to the early modern time，the situation was different. Based on the development of European guilds，the increasing of long-distance voyages，the epidemic of diseases，and advance of military technologies，the ship doctors became essential men on ships gradually. Most of ship doctors are surgeons who came from Barbers and Surgeons guilds in Europe. At beginning，they faced many difficulties，including shortage of people，difficulty of recruitment，low status，lacking of professional skills. No matter how，if there were no ship doctors in times of the great navigation，it was very difficult for European countries to carry out the exploration and expansion overseas.