1. promoted the friendly trade between Ming Dynasty and East China Sea, Indian Ocean, Africa and Southeast Asian countries along the Red Sea. China's silk and porcelain, as well as China's ancient civilization, were taken abroad. Every time he went to a country, he first submitted a letter to the king, and presented them with gifts on behalf of the Ming emperor, hoping to have friendly exchanges with them. Military officials from all over the world expressed warm welcome when they saw the large scale of the generals and the friendly attitude of the officials, and did not mean to show off their force or threaten others. When people heard that the Ming fleet was coming, they all rushed to the seaside to watch. They were surprised at the treasure ship they had never seen before. At that time, China's heavy silk and porcelain had long been famous overseas. People along the way were very happy to hear that the fleet had these items. They exchanged spices, corals, jewelry and so on for China's local products. Businessmen from all over the world are very happy to do business with China people. Many people also give gifts to China guests to show their friendly feelings.
2. Showed the power and wealth of the Ming Dynasty and publicized the positive foreign policy of the Ming Dynasty.
Zheng He's voyages to the West promoted the overseas Chinese's southward migration, promoted the development of Southeast Asia, and brought advanced civilization and modes of production.
4. It laid the blue land of China and provided a historical basis for solving the South China Sea issue.
But the purpose of Zheng He's voyage to the West is not for scientific exploration, nor for developing overseas trade, but for diplomatic needs, even just to tell those small countries in Nanyang that there is a powerful Ming Dynasty in your north!
On the other hand, Zheng He's seven voyages to the Western Seas cost millions each time, resulting in empty treasury, social unrest and inflation. When he went to sea for the sixth time, the price was more than seven times higher than that of the first time!