Regional trade flow and the hierarchical structure of China's high-speed rail hub

In this paper, the national hub cities, regional hub cities and district hub cities were analyzed. We used the gravity model to estimate trade flows between hub cities. We focused on the analysis of the trade structure characteristics for the hierarchy structure of the high-speed rail hub cities, and then set a regional trade difference index and regional integration index. The results show that the regional trade between high-speed rail hub cities has grade difference and spatial agglomeration characteristics. The developing of high-speed rail network has improved economies scale of hub cities, strengthen the function of hub, expend the range of hub Market and promote the balanced trade development in other cities, and also improved the China's overall level of regional economic integration. The high-speed rail is conducive to the coordinated development of the national economy. But at the same time, there are some negative externalities. It increases the difference of regional hub cities. Therefore, in the development of high-speed rail, the government should introduce more targeted policies to guide the rational layout of the industry, to promote the coordinated development of regional economy.