Abstract: Karst environment is distributed largely in Southwest China. Soil and vegetation are the most sensitive elements to the variation of Karst environment. The weathering of carbonate is important soil formation mechanism in Karst areas, but its soil forming ability is so poor that soil layer thickness becomes thin by the water erosion, though the soil loss is insignificant but serious. The character of Karst plants is firmly connected with the environment condition, i.e., lack of water, richness of Ca²⁺, poor soil and shortage of organic matter , the plants have low pace growth and low life-form resource, and is vulnerable under the disturbance of irrational human activities. Therefore, the rocky desertification is the end of Karst ecosystem degradation, but these degradation processes are depended on different land use patterns. Further, this paper discusses the assessment of the fragility on Karst ecosystem and raises vital problems on how to improve productivity. Finally, this paper suggests some solutions about rehabilitation of ecology to solve the problems of man-land relation in Karst environment in Southwest China.