The grandure of the fleet would dramatize the superior majesty and power of the Ming empire to peoples of distant lands, causing states of South and Southeast Asia to be incorporated into the tribute system. The fleet expected to receive demonstration of submission from rulers of areas it visited, and many foreign countries surely would acknowledge China's superiority in order to increase their trade. If people did not recognize Chinese greatness, the admiral might have to use force, but the Chinese expected that the encounters would be peaceful since it was only fitting that as many people as possible should come under the sway of the Son of Heaven. Opening trade routes and establishing trade through the exchange of tribute and gifts was a major goal of the voyage. Since Zheng He was a Muslim, he would be able to establish good relations with Muslim trading communities as well as with Chinese traders in the ports the ships visited.
Medical research appears to have been another motivation for the voyages.
Several devastating epidemics had swept through the Middle Kingdom, and many doctors and pharmacists went on the voyage, instructed to look for herbs and other medicines. Finally, Zheng He was to look for any signs of the deposed Emperor whom some people believed was still alive and attempting to build up a power base somewhere in Southeast Asia. The fleets were impressive, and many ambassadors and rulers from areas the fleet visited came to the Ming court with tribute, acknowledging Chinese superiority. However, several factors contributed to making many in the court, particularly the Confucian scholars around the Emperor, oppose the voyages. Once the tribute relationship had been reestablished, and the explorations completed, some questioned the need to send repeated voyages.