In order to transport cereals from south to north

sea transportation developed during Yuan and Ming Dynasty. Sea transportation made great influence on the development and social economy on coastal cities. Two modern metropolises

Shanghai and Tianjin developed on the basis of sea transportation. Sea transportation also promoted active commodity economy and development of marine technology and marine technology. Sea transportation had undergone a winding course during Yuan and Ming Dynasty. Yuan Dynasty is a new country across Eurasia born with spirit of adventure. At that time

western colonialists didn’t start their overseas expansion. Coastal region of China at that time was peaceful and safe which provided favorable conditions for the development of sea transportation in Yuan Dynasty. In the Middle of Ming Dynasty

coastal region of China was often disturbed by Japanese pirates

therefore

government restricted foreign trade. Ban on foreign trade encouraged western colonialists’ invade and harass to coastal region. Flourishing sea transportation in Yuan and early Ming Dynasty disappeared. China lost the good opportunity in integration of Chinese and western technology and transformation to modern society. It is a great pity.