The objective of this study is to analyze the tourism spatial interaction that defines two scenarios, i.e., the actual one with the current high-speed rail (HSR) network, and the future one with an extension of the HSR network, considering as a case study the Capital region of China. The impact of HSR on the spatial distribution characteristics is investigated. The main outcome of this study is that the extension of the HSR network in the future scenario will significantly increase the total tourism spatial interaction and will reduce the spatial difference. What this paper adds to the current knowledge about HSR and tourism is that smaller cities, such as Tangshan, Zhangjiakou, and Chengde, connected via HSR to core cities will benefit the most from the HSR network’s operation. Those cities should take the HSR network as a development opportunity to enhance their attractiveness and strengthen their marketing to achieve sustainable tourism competitiveness. The study found that effects can also be registered on larger cities, but they are smaller. So, larger cities, such as Beijing and Tianjin, should reassess their attractiveness to the tourist market and take corresponding countermeasures. The findings of this study can be used by tourism management authorities to develop short-term and long-term plans.