Significant differences exist in the dominant driving factors of rocky desertification evolution in varying temporal periods of mountainous karst areas in southwest China. However, previous studies were primarily conducted in specific periods. In this study, taking Bijie city (one of the areas most seriously affected by rocky desertification in southwest China) as an example, we analyzed the spatio-temporal evolution pattern of rocky desertification in Bijie city in recent 35 years by introducing the feature space model and the gravity centre model, and then clarified the dominant driving factors of rocky desertification in the study area in varying temporal periods based on GeoDetector. The findings were as follows: (1) the proposed point-line BLI-NDVI feature space model has higher applicability for rocky desertification monitoring with the overall inversion accuracy of 92.0 %; (2) during 1985–2020, there was an overall decreasing trend (weakening-aggravating-weakening) of the rocky desertification; (3) the spatial distributions and migration trajectory of gravity centre of rocky desertification indicated that the rocky desertification degree in the western parts was more severely than that in the eastern regions; (4) during 1985–2020, the land use and POP density have become the dominant factors of rocky desertification instead of vegetation coverage and temperature.