Background Karst rocky desertification is a typical ecological environment issue in the southwest karst region. How to correctly understand the coupling relationship between karst rocky desertification and urbanization is a necessary condition for formulating karst rocky desertification control policies and guiding the sustainable development of cities and towns.

Methods Based on Google Earth Engine calling Landsat images, an evaluation model of karst rocky desertification degree was constructed and comprehensive karst rocky desertification indexes were calculated. The comprehensive urbanization indexes were calculated using the entropy method and the linear weighting method, and the temporal and spatial characteristics of the evolution of the coupling coordination degree of karst rocky desertification and urbanization from 2000 to 2020 were explored with the help of the coupling coordination degree model.

Results 1) The degree of karst rocky desertification shows a downward trend, but the regional differences are obvious. Severe and very severe karst rocky desertification is concentrated in the central and southwestern regions; the level of urbanization is developing rapidly, and the urbanization level in the eastern region is higher than that in the western region. 2) The coupling and coordination degree between karst rocky desertification and urbanization has been continuously improved, gradually transitioning from "uncoordinated development, urbanization lags behind" in 2000 to "transformed development, karst rocky desertification lags behind" in 2020. 3) The faster the urbanization level improves in counties and districts, the more obvious the effect of karst rocky desertification control, and the corresponding coupling coordination degree is higher.

Conclusions The results of this study can provide reference for the local government to better formulate sustainable development urbanization plan and better balance urbanization and ecological environmental protection.