| Taking the typical Karst hill Yunnan Stone Forest as an example, by field investigation and sampling and indoor analysis, replacing time series by space series, this study had reseached the group characteristics and soil physical and chemistrical and biological qualities of four stages of the degradation of the Karst hill Yunnan Stone Forest: forest community, tree-bush community, bush-herb community, herb community, to explain the relationship between soil and plant diversity, to demonstrate the soil degradation properties and their causes, and to provide support for Yunnan Stone Forest ecosystem degradation reparation.The results showed that, with the vegetation destroyed, there were decreases in soil fertility quality in varying degrees. Namely, the soil structure was poor. The soil texture and porosity also deteriorated. The content of the Soil water, organic matter, N and P already dropped. The number of its micro-organisms reduced.The soil enzyme activity also declined. However, pH, K and bulk density increased. With the degradation of soil quality, the indices of the species, diversity and biomass in degradation stage of the four typical, turned to be a clear downward trend. Specifically, the indices of species, richness, Shannon-Wiener, Simpson, Pieluo, and biomass, decreased respectively from 60 to 16, 54 to 13, 2.675 to 1.086, 0.465 to 0.166, 0.384 to 0.158, 85.367kg/m2 to 54.86kg/m2 .The soil analysis of the relevance and principal component was informed that bulk density, pH, organic matter, nitrogen (N), phosphorus (P), and potassium (K), all are closely related. Under certain conditions, they can be used as the main indicator of soil fertility. From the analysis of the relevance between the soil and plant diversity, it can be seen that destruction of vegetation has affected soil physical and chemical properties greatly, and soil degradation has caused the decline in species diversity.
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