The Evolution of Port System in the Yangtze River Delta from the Tang Dynasty to Modern Times

The main port in the Yangtze River Delta shifted from Yangzhou in the Tang Dynasty to Ningbo and Shuangyu in the Song, Yuan and Ming dynasties, and afterwards to Shanghai before the opening-up in modern times. It indicates the tendency from north to south and from south to east. The main port and other regional ports constructed an organic and systematic network. The end of this paper studies the port location, natural environment, hinterland development, international relations, and analyzes the factors that made possible the shift of the main port.