Abstract: In the middle and early Northern Song Dynasty, Gan Pu town completed the military nature to the nature of economic transformation. In the Middle and early Southern Song Dynasty, its economic function was further strengthened. Later in the Southern Song Dynasty, the Gan Pu town was declining, and its decline was not related directly to the separation of Bao Lang saltworks, but was related to the change of political and military situation at that time. After the beginning of the Duan Ping year, Meng and Yuan launched the war against Song Dynasty, so North-South relations tended to be tense; as a gateway to Linan, Gan Pu towns military position was highlighted, which affected its marine transportation, then it was to decline. The rise and fall of the Gan Pu town reflects the contradiction between the trade in Jiangzhe areas and coastal defense in the Southern Song Dynasty, but also encourages us to reflect on the “continuity” problem in the history of Jiangnan town development.

Key words: Gan Pu town, Bao Lang saltworks, sea salt, marine trade, North-South relations