For the most important economic phenomenon in modern Chinese history, the treaty ports system, we can use the research methods of contemporary economic geography, GIS, economics, and so on, to investigate the pattern of modern China’s economic geography and regional economic differences through the investigation of historical data. More than 100 treaty ports in modern China have gradually formed a geographical pattern of opening up to the outside world from the coastal, riverside to border areas, which has provided conditions for modernization, promoted the spatial expansion of modern capitalist mode of production, and reconstructed China’s economic regions. In this paper, first of all, through the discussion of the geographical spatial distribution of the transit duty trade in the treaty-ports system, we preliminarily determine the influence areas of some larger treaty ports; then, with the support of quantification and GIS methods, especially the spatial interactive models, economic regional changes under the influence of modern Chinese trading ports are calculated. Based on this result, the treaty ports system can be regarded as the representative and systematic research object of regional economic modernization, which directly affects the economic geographical pattern of contemporary China, and provides a historical and practical reference for the current economic geographical division of China.