Exploring the development of tourism economy in arid and semi-arid regions has certain reference value for guiding the sustainable and high-quality development of tourism in Ningxia, a province in the upper reaches of the Yellow River. Taking 2010, 2015 and 2019 as time sections, the study analyzed the spatio-temporal characteristics of the evolution of the tourism economic network structure in Ningxia based on the modified Gravity model and social network analysis method. The results showed that: ① Ningxia presents a network spatial pattern of regional tourism core cities radiating and driving surrounding cities, forming a diagonal triangular tourism economic network space with Yinchuan as the center and Zhongwei City, Wuzhong City, and Shizuishan City closely connected. ② The connection between regional tourism development in Ningxia has gradually evolved from unipolar to multi-level, with an increasing number of intermediary cities. The core city of Yinchuan has been continuously consolidated and developed, and intermediary cities have gradually increased from Yinchuan City to Zhongwei City and Wuzhong City. ③ The overall tourism economic connection in Ningxia is becoming increasingly close, and the connections and cooperation between various regions are constantly changing, presenting a development trend of spatial order reconstruction. Finally, this article analyzes the reasons that affect the evolution of the spatial structure of Ningxia’s tourism economy network from four aspects: geographical environment, transportation distance, resource endowment, and policy support.