The construction and opening of high-speed railroads have brought new development opportunities to China’s ethnic regions, which are economically backward but rich in tourism resources. From the perspective of the impact of high-speed rail on regional tourism, this paper briefly analyzes the homogenization effect and accessibility effect that the construction of high-speed rail brings to the corresponding region. Accordingly, it puts forward the relevant research hypotheses on the impact of high-speed rail on regional tourism and analyzes the current situation of tourism market development in China’s A ethnic region. Under this premise, the model of high-speed railroad influence on tourism development level is designed and relevant research variables are selected. Based on the model, the empirical analysis of the impact of high-speed railroad on tourism in ethnic region A is launched. The study points out that the opening of high-speed railroad significantly promotes the total tourism income of ethnic region A at the 1% level, i.e., the opening of high-speed railroad has a positive positive effect on the tourism development of ethnic regions.