Abstract: Qujing city is located in the upper reaches of the Yangtze River and the source of the Pearl River, and has an important ecological location. It is of great significance to explore the dynamic and evolution process of rocky desertification in a long time series in this area. In this study, based on Landsat5, Landsat8, DEM, etc., we obtained the rocky desertification distribution from 1990 to 2020 through GEE cloud platform and decision tree classification, and analyzed the spatial and temporal change characteristics and evolution process of the rocky desertification. The results show that: (1) the overall rocky desertification in Qujing city was dominated by potential and no rocky desertification; in 31 years, the rocky desertification area in Qujing city decreased by 1728.38 km², while the total area increased by 1936.61 km², and the overall rocky desertification was significantly improved.(2) From 1990 to 2020, the overall change rate of rocky desertification in Qujing is-57.61 km²/a, and the change rate is decreasing: extreme intensity> intensity> moderate> mild> no> potential desertification.(3) In 31 years, the evolution direction of rocky desertification in Qujing is mostly unvariable, with 7967.67 km², accounting for 61.39%; the continuous transformation and fluctuation transformation reflecting the improvement of rocky desertification was 3197.03 km², or 24.63%; the deterioration area was 558.52 km², accounting for 4.3%,the results showed that the stony desertification situation in the study area showed a general improvement trend.

Key words: karst rocky desertification, GEE, evolution track, Qujing