Objective To reveal the long-term ecological-quality changes and scale-dependent influencing mechanisms of the Taklamakan Desert and its surrounding oasis-desert ecotones, and to provide a basis for ecological monitoring and zoned management in extremely arid regions.

Method Based on multi-source remote sensing and geospatial data from 2000 to 2025, a modified remote sensing ecological index (E) suitable for sparse vegetation, bare land, and salinization backgrounds was constructed. Theil-Sen trend estimation, the Mann-Kendall test, centroid migration, Geodetector, multiscale geographically weighted regression (MGWR), and the Hurst exponent were combined to analyze the spatiotemporal evolution, regional spatial differentiation, and local associations of ecological quality.

Result (1) Ecological quality remained generally low with pronounced interannual fluctuations. Poor and relatively poor classes dominated over the long term, whereas medium- and high-quality patches were mainly distributed in the southern piedmont and along the northern oasis margins. In 2020, the area proportion of the 0–0.2 class decreased to 0.83%, mainly shifting to the 0.2–0.4 class. (2) Geodetector showed that elevation (q = 0.38) and air temperature (q = 0.30) had relatively high explanatory power for the spatial differentiation of E; the interaction explanatory power of elevation with terrestrial water storage anomaly, road distance, precipitation, and soil moisture was further enhanced. (3) MGWR showed that the local coefficients of elevation and air temperature differed in direction between the desert interior and the peripheral piedmont. Positive associations of precipitation and soil moisture were mainly concentrated around oasis margins, whereas negative associations of human-activity proxies were mainly distributed near towns and transport corridors. (4) Areas with H > 0.5 accounted for 80.10%. Combined with Sen slopes, the central-eastern desert was dominated by persistent improvement, while the western and southern margins and the northern ecotones showed higher risks of persistent degradation or reversal of improvement.

Conclusion Ecological quality in the Taklamakan Desert exhibits marked spatial heterogeneity and scale effects. The regional pattern is mainly related to the topographic-thermal background, whereas oasis-desert ecotones are more sensitive to water conditions and human activities.