Coupled coordination of tourism eco-efficiency and economic development in China: measurement, spatio-temporal evolution, and spatial spillover

• The interactive effect of tourism eco-efficiency (TEE) and high-quality economic development (HQED) is proposed. • Coupling coordination degree model for measuring TEE and HQED coordinated degree (THCD). • THCD leaped from moderate imbalance (0.394) to low coordination (0.547). • Spatio-temporal characteristics of THCD based on Hu's line are remarkable. • The influencing factors of THCD have a significant spatial spillover effect. This study addresses a key research gap in understanding the synergistic relationship between tourism eco-efficiency (TEE) and high-quality economic development (HQED) by constructing a two-way coupling theoretical framework. Employing panel data from 30 Chinese provinces (2011–2019), the research measures TEE using a Slack-Based Measure-Data Envelopment Analysis (SBM-DEA) model with undesirable outputs, and evaluates HQED applying the entropy weight-TOPSIS method. The coupled coordination degree (THCD) model quantifies system synergy, while spatial autocorrelation analysis and a spatial Durbin model (SDM) are employed to reveal spatio-temporal patterns and driving mechanisms. The findings indicate that TEE growth (4.22% annually) outpaces HQED (0.66%), with THCD transitioning from moderate imbalance (0.394) to basic coordination (0.547), and showing a distinct east-central-west spatial gradient. A significant spatial clustering of THCD is confirmed, with population size, environmental regulation, and financial development identified as key drivers of spatial spillover. The study's originality lies in its dual-system synergistic framework, offering a novel perspective on ecological-economic mutual feedback and extending theoretical paradigms beyond single-factor analyses.