Abstract: As the junction of national interests between sovereign states, border areas, and border ports in particular, have direct effects on carrier cities. This paper takes the four border ports in Dehong prefecture, Yunnan province, as the micro-scale units to discuss the influencing factors of the border ports on the carrier cities at the county scale by the panel data model and the RCI index comparison. The findings show that: 1) total imports and exports and total freight volume of port, and the number of people entering and leaving the port all have a positive effect on the carrier city, and the influence of logistics is the most prominent. The flow of people and logistics become an important form connecting border and carrier city, both of them also have positive effect on the development of carrier city. The customs clearance functions and border trade functions of port are highlighted. 2) the distance between the border port and the carrier city has a significant impact on the development of the carrier city. The greater the distance is, the more obvious the constraints will be, the friction resistance decreases with the reducing of the spatial distance. Through the comparison between Ruili and Yingjiang ports, it can be easily seen that the distance factor has a greater impact on the actual development of the carrier city. 3) among the four ports, only Ruili port shows a vigorous driving forces for the development of carrier city, while the forces at the rest ports, including Wanding, Zhangfeng, Nabang, are weak. Ruili port has great advantage in the flow of people, logistics and the distance from carrier city, and has significant trend of border-city integration, which promotes the development of the carrier city. Both the port scales of Wanding and Zhangfeng are small, and their interactions with carrier cities are weak, thus the port functions are not fully utilized. The distance between Nabang port and carrier city is longer, that restricts the action of the port to promotion the development of the carrier city. Finally, this paper puts forward some suggestions about the differential development of the ports. In order to promote the development of the local industries, Ruili port should play its geographical advantage and cluster effect for further realizing the border-city integration development. Wanding port should strengthen the optimization of import and export commodity structure, enhance the port's import and export capacity and scale, for achieving the interaction with the development of Ruili. Zhangfeng port should expand its scale, increase the flow of people, logistics and its customs clearance capacity, while strengthening the production, technical level of the towns and villages around the port, thereby increasing the value of goods. Yingjiang should break the terrain restrictions, and vigorously improve the quality of traffic between itself and the Nabang port to shorten the actual distance between them. Relying on its good ecological resources, the local government of Yingjiang should energetically promote Sino-Myanmar agricultural cooperation and eco-tourism corridor construction, and build “Yingjiang-Myanmar” green corridor, so as to change its location disadvantage into late-mover advantage.

Key words: micro-scale, border ports, carrier cities, the panel data model, Dehong Prefecture