It was noticed long time ago that Karst rocky desertification is gradually developed into the third-largest ecological problem. Remote sensing is mostly used in the research of Karst desertification. However, the previous research used original imagery, so it cannot effectively interpret the characteristic of rocky desertification. This paper chooses the first three components of the KT transform of ETM+ data to establish rocky desertification exponential model. Four variables: index of Karst (IK), brightness, greenness, and wetness were extracted to characterize the rocky desertification in the study. The last three variables are the first three components of the KT transform. Their interrelationships were examined using a correlation matrix. The investigated results indicate that index of Karst is mostly correlated with the brightness (r= 0.64), but negatively correlated with greenness (r= −0.81) and wetness (r= −0.51) (at 90% confidence level). These findings can be used to mitigate rocky desertification by city planners, environmental managers, and other policy makers for designing measures.