The Liujiangang Harbor is located at th Lou River(in River) Mouth,at the northeast of Taihu Plain and on the south border of Yangtze Estuary.In the Early Ming Dynasty which selected Nanjing as its capital,the Tiemuer Empire was rising in the Central Asia and the Silk Road was hindered at that time.The Ming Dynasty had to over again open up the Maritime Silk Road to develop foreign trade.Before the Middle Yaun Dynasty,the historical record Showed that sediments were deposited in the Lou River.The water depth in the channel was getting shallow,and it is difficult to built harbour and navigation Channels.Owing to the fact that in Ming Dyansity the Lou River was regulated, the water depth for harbour and navigation was improved.In the short Perid of the Early Ming Dyansty the Lou River had the best coditions for builting harbours in the region of the Yangtze River.The facts mentioned above resulted in the flourish of the Liujiagang Harbour which became the departure harbour of Zheng He's sailing to the west Ocean.In the Middel Ming Dynasty,the south bank of the Yangtze Estuary collapsed because of erosion by water flow and tide,and the Liujiangang Harbour and the Liujiahe Town were collapsed.At the same time,the Lou River had a serious deposition.Zheng He's sailing to the West Ocean was ended.In the Middle and Later Ming Dynasty,the coasts of China were barassed by the Japanese pirates,and the Grand Canal was repaired and reopeaned for water transport.All these led to the declining of the Liujiagang Harbour.