This study aims to scientifically measure and evaluate the evolutionary state of "spatial equilibrium" in tourism ecosystems to promote the sustainable development of tourist destinations. First, based on the paradigm of systems science, the study explores the dynamic balance and equilibrium state between efficiency and equity in the evolutionary development of tourism ecosystems. A theoretical evolutionary model of tourism ecosystem "spatial equilibrium" is constructed, integrating the "natural resource utilization efficiency subsystem" and the "social equity development subsystem." Subsequently, a measurement index system comprising nine dimensions is developed based on the Pressure-State-Response (PSR) model. The actual evolutionary state of "spatial equilibrium" in the tourism ecosystem is quantitatively assessed using a combination of the entropy weight method, range method, and fuzzy clustering method. Finally, a comparative analysis between the empirically measured values and the theoretical values of "spatial equilibrium" in the China Danxia (Chishui, Guizhou) World Natural Heritage site yields the following findings: (1) The constructed theoretical evolutionary model effectively fits the evolutionary trajectory of the "spatial equilibrium" in the case study area’s tourism ecosystem. The empirical state values exhibit short-term oscillations around the theoretical evolutionary values, displaying a long-term "S-shaped" evolutionary trend. (2) The theoretical model estimates that the evolutionary cycle of "spatial equilibrium" in the tourism ecosystem of China Danxia (Chishui, Guizhou) is approximately 50 years. During the period from 2000 to 2020, the tourism ecosystem in China Danxia (Chishui, Guizhou) underwent an evolutionary process from lagging to overloading and finally toward equilibrium. Compared to the theoretical values of "spatial equilibrium" evolution in the case study area, the empirical state values exhibit a "slow progress leading to regression" trend. (3) In 2000, the tourism ecological state index of China Danxia (Chishui, Guizhou) ranged between 0.089 and 0.180 (fifth level). After nearly 20 years of gradual recovery, by 2020, the index had improved to above 0.2362 (third level).To some extent, this study achieves the fitting and dynamic assessment of the evolutionary process of "spatial equilibrium" in tourism ecosystems, advancing research in this field from static evaluation toward diversified, dynamic, and quantitative approaches. This provides a systematic theoretical and methodological foundation for the sustainable development of tourist destinations.